玉米淀粉的化学与物理修饰

本论文以淀粉为研究对象，从高分子的基本理论出发，通过化学与物理的手段利用淀粉上的经基，调控了淀粉大分子链的聚集态结构，探索了将淀粉这种天然储能高分子变为实用的材料的可能性。采用化学交联的手段制备了交联淀粉膜。研究了淀粉交联后的老化过程和水在其中的结合状态。试验证明，交联键的引入使得淀粉的结晶和局部有序结构程度下降，让淀粉大分子的聚集态结构趋于均一化的同时，释放出大量的"自由轻基"。改变了淀粉膜的吸水能力和淀粉内部水分子的结合状态，综合交联与水分子的增塑作用，可以在一定程度上调控淀粉膜的力学性能。淀粉和生物降解大分子（PCL、PHBV）制备的IPN材料显著的提高了淀粉的耐水性能。通过实验证明DMSO／water配合体系作为一种高效、安全的组合溶剂对淀粉的醚化反应非常有效，取代度最高可达1．81。控制节基氯和淀粉重复单元的摩尔比、反应温度、DMSO/water组合溶剂的不同配比等可以制备出不同取代度的节基淀粉醚。经证实，淀粉的醚化反应主要发生在脱水葡萄糖环上的2位碳原子的经基上，其次发生在C-6、C-3碳原子的经基上。醚化后的淀粉即使很低的取代度（Ds：0．0546）时淀粉在x一射线衍射曲线上的结晶峰已经完全消失了。发现了稳定、高效的淀粉增塑剂FSDT。使用FSDT成功的对淀粉进行了塑化处理，而且塑化后的淀粉一年后仍保持优良的机械性能，特别是当FSDT的含量超过30％以后，淀粉从无法加工的脆性材料变成了类似弹性体的材料，在此基础对淀粉进行了化学交联，交联后样品的断裂伸长率有了更进一步的提升，达到470％。

活化剂对黑土磷有效性及玉米产量影响研究

磷肥低利用率造成了经济损失，给人们赖以生存的环境造成了不良后果，因而提高磷肥利用率意义重大。温度对植物磷营养及土壤磷有效性影响较大，然而探索不同温度下磷活化剂的效应（特别是对磷组成的影响）少有研究。本文以腐植酸（HA）、柠檬酸铵、活化剂H2为供试磷素活化剂，以吉林黑土为供试土壤，研究活化剂对土壤磷有效性及玉米产量的影响。 ①培养试验表明：自然不施磷水平下，在一定温度范围内，高温更有利于Olsen-P含量增加。施入磷肥后，情况相反，特别是培养前期，高温加速磷的固定。活化剂能有效提高土壤Olsen-P量，10℃和20℃时活化效果较好，主要通过增加Ca2-P、Ca8-P和Al-P含量来实现。10℃时三种活化剂活化能力为柠檬酸铵＞HA＞活化剂H2，分别提高土壤Olsen-P量达40.9%、33.1%、23.2%；20℃时活化能力为HA＞柠檬酸铵＞活化剂H2，分别提高32.4%、24.9%、16.7%；30℃时无明显增效。活化剂对无机磷总量无明显增效。通过相关分析、通径分析和回归分析证实，Al-P和Ca2-P是黑土有效磷的主要组分，与Olsen-P有极显著的相关性，其它形态的磷可以通过影响Al-P和Ca2-P的含量间接作用于Olsen-P。 ②大田试验表明：苗期-抽穗期-腊熟期各处理土壤有效磷含量都呈下降趋势，特别是苗期-抽穗期，有效磷含量急剧降低，下降幅度为47.1%~50.2%，活化剂处理都一定程度地减缓了有效磷下降的趋势。活化剂不同幅度的增大了玉米产量，以H2（450kg/hm2）产量为最，比对照增产9.32%，其次为柠檬酸铵（15kg/ hm2）和HA（150kg/ hm2），分别增产5.99%和4.99%。玉米产量与抽穗期土壤有效磷的相关性相对较大。活化剂处理对玉米产量的提高主要是通过增加千粒重来实现的。

白腐菌选择性降解木质素的研究

对15株白腐真菌进行了以玉米秸秆为基质的初步筛选，从中获得一株选择性系数较高的菌株Y10，并对其降解玉米秸秆的情况进行了研究。结果表明，在30天的培养过程中菌株Y10对玉米秸秆降解的选择性系数都大于1，第15天选择性系数最高为3.88。对未经降解和降解过的玉米秸秆分别作了紫外光谱和红外光谱分析，结果表明，经该菌降解后玉米秸秆的化学成分发生了很大变化，且木质素的降解程度要大于纤维素的降解程度。对菌株Y10进行了ITS-5.8S rDNA序列鉴定，初步判定其为Cerrena sp.。 为了考查不同的外源添加物对菌株Y10降解玉米秸秆的影响，在以玉米秸秆为基质的固态发酵培养基中分别添加了7种金属离子、8种碳源、6种氮源。结果显示，这7种金属离子均能促进木质素的降解，并且一定浓度的某些离子明显抑制纤维素的降解；其中添加0.036%的MnSO4·H2O和0.36%的MgSO4·7H2O对纤维素降解的抑制作用比较强，降解率分别为0.96%和1.31%，木质素的选择性系数分别达到了34.40和20.17。8种碳源中除麦芽糖外都能促进木质素的降解，除微晶纤维素外都明显促进纤维素的降解。6种氮源中酒石酸铵、硫酸铵、草酸铵和氯化铵的添加都会使该菌生长变慢，而且氮源浓度越高菌丝生长越慢。外加碳源和金属离子对半纤维素降解和选择性系数的影响不大。 同时对菌株Y10在液态培养下产木质素降解酶的条件和培养基做了优化。结果表明，在初始产酶培养基中，菌株Y10的漆酶酶活在第10d达到最高，锰过氧化物酶酶活在第11d达到最高，基本上检测不到木质素过氧化物酶。菌株Y10产漆酶的最适温度为32℃，最适PH为6.0；产锰过氧化物酶的最适温度为32℃，最适PH为6.5。菌株Y10产漆酶的最佳碳源为甘露糖，最佳氮源为酒石酸铵，最适诱导剂VA浓度为3 mmol/L，最适表面活性剂TW-80浓度为1%。 利用响应面法对其产漆酶的培养基进行优化，优化后的培养基配方为葡萄糖10.00 g/L，酒石酸铵0.50 g/L，大量元素296.50 ml/L，微量元素100.00 ml/L，NTA 1.40 g/L，VA 5.00 mmol/L，吐温-80加入量为0.10%。进行了菌株Y10产漆酶的验证实验，实测酶活为5282.56 U/L，与预测酶活5162.73 U/L接近。在优化后培养基中，菌株Y10在第14 d达到生长的最高峰，第20 d时，漆酶酶活最高，为11325.00 U/L；第16 d时，锰过氧化物酶酶活最高，为30.77 U/L。 对菌株Y10的漆酶酶学性质做了初步的研究，结果显示，酶反应的最适温度为40℃-65℃，最适PH为3.0。在40℃，PH=3.0时，漆酶催化ABTS反应的米氏方程为 。 Fifteen white-rot fungi based on corn stalk were screened. One white-rot fungus Y10 with high selectivity value was obtained. The degradation of corn stalk was initially studied. The results indicated that the selectivity value was above 1 during the 30 day-cultivation and the highest was 3.88 after 15 days. The composition of untreated and treated stalk was analyzed through ultraviolet spectroscopy and infrared spectroscopy. It was found that the composition of treated stalk was greatly altered and the degree of the degradation of lignin is greater than the cellulose. Y10 was identified as Cerrena sp. by ITS -5.8S rDNA sequence analysis. The influence of metal ions, carbon sources and nitrogen sources on corn stalk degradation by white-rot fungus was studied. While all seven metal ions could promote lignin degradation, the cellulose degradation was best inhibited at certain ion concentrations. Notably, when 0.036% MnSO4·H2O and 0.36% MgSO4·7H2O were added into the medium, the cellulose degradation was restrained to the extents that the coefficients of lignin selectivity rose to 34.40 and 20.17 respectively. It was also found that all carbon sources except maltose can promote lignin degradation. The addition of carbon sources other than microcrystalline cellulose significantly promoted cellulose degradation. The addition of the nitrogen sources, ammonium tartrate, ammonium sulfate, oxalate, ammonium chloride, resulted in remarkable inhibition to mycelium growth; the larger the concentrations of nitrogen sources are, the slower the mycelium grew. The addition of carbon sources and metal ions had less impact on the degradation of hemicellulose and selectivity value. Meanwhile, we optimized the conditions and culture medium of the lignin-degrading enzyme production of strain Y10. The results showed that in the initial culture medium, the Lac activity was highest at the 10th day, the MnP activity was highest at the 11th day and the LiP could not be detected. The optimum condition of Lac was at temperature 32 and PH =6.0 and the optimum condition of MnP was at temperature 32 and PH =6.5. The optimum carbon source for Lac was seminose, the optimum nitrogen source was ammonium tartrate, the optimum content of VA was 3 mmol/L, the optimum content of TW-80 was 1%. PB and RSM were used to optimize the culture medium of laccase by white-rot fungus Y10. The optimum culture medium was consist of glucose 10.00 g/L, ammonium tartrate 0.50 g/L, macro elements 296.50 ml/L, trace elements 100.00 ml/L, NTA 1.40 g/L, VA 5.00 mmol/L, TW-80 0.10%. Under the optimal conditions, the activity of laccase was 5282.56 U/L and the experimental value agreed with the predicted value 5162.73 U/L. The biomass was highest at the 14th day, the Lac activity was highest at the 20th day, the MnP activity was highest at the 16th day. The results of the studies on the characteristics of Lac showed that the optimum temperature for Lac activity is 40℃-65℃ ; the optimum PH for Lac activity is 3.0 and under 40℃，PH=3.0, the Michaelis-menten equation of Lac catalized ABTS oxidation was .

厌氧复合菌系的筛选及含纤维素原料预处理复合菌剂的研究

本文从不同厌氧生境中获得7组(C-2、Y-2、L-2 、NZ、H-3、CZ、L-3)具有纤维素降解能力的复合菌系。经过不断传代、淘汰纤维素降解能力降低的菌系，最后得到一组高效、传代稳定的厌氧纤维素分解复合菌系L-3。该菌系可使滤纸在42 h内溃烂，并能在分解纤维素的同时产氢气。对L-3复合菌系的产酶条件进行了研究，结果表明，在实验范围内该菌系的产酶最适条件为：pH 6.5，温度37 ℃，接种量5 %，最佳碳源为滤纸，最佳氮源为硫酸铵。第10天测得羧甲基纤维素酶(CMCase)、滤纸酶(FPA)、外切葡聚糖酶(C1)、β-葡聚糖苷酶(β-glucodase)的酶活分别为0.216 U/ml、0.101 U/ml、0.132 U/ml、0.002 U/ml，滤纸失重率70.6 %。发酵代谢产物乙醇和丁酸含量分别可达1378 mg/L 、2695 mg/L，发酵产生的气体中氢气含量最高可达70.2 %。DGGE结果表明该菌系主要由14种菌组成，其中有三株菌在发酵前后菌数发生了明显的变化，说明在以滤纸为底物的降解过程中，这三株菌起到了重要作用，对这三株菌进行了分子生物学鉴定，初步定为Clostridium phytofermentans、Clostridium cellulovorans、Desulfovibrio sp。 利用实验室分离得到的纤维素降解菌，最终配制出由10、X-1、X-13、ST-13、L-3组成的好氧-厌氧纤维素降解复合菌剂。以秸秆为发酵底物，菌剂接种量1%，利用复合菌剂预处理后的秸秆，发酵总产气量相对于对照提高了71.62%，甲烷含量最高可达70.08%。 A group of microbial consortia L-3 was isolated from the anaerobic fermentation residue of corn stalk, which could degrade cellulose and produce hydrogen. The CMCase, FPA, C1 and β-glucosidase activity of L-3 could reach to 0.216 U/ml, 0.101 U/ml, 0.132 U/ml and 0.002 U/ml, respectively. In the filter degrading process, the filter paper collapsed in the liquid culture within 42 h and the filter degrading rate could reach to 70.6% in the 13 days, meanwhile, hydrogen was determined and the highest hydrogen content was 70.2%. The optimum cellulase-degrading conditions were filter papaer as the carbon source, (NH4)2SO4 as the nitrogen source, 37 ℃ and pH 6.5 in this experiment. DGGE results showed that the microbial consortia L-3 mainly included 14 strains. The amount of 3 strains were changed during the fermentation. These strains were identified as Clostridium phytofermentans、Clostridium cellulovorans、Desulfovibrio sp by 16S rDNA sequence analysis. The cellulose- degrading microbial agent was composed by 10, X-1, X-13, ST-13, L-3 which were isolated in the laboratory. The straw pretreated by cellulose-degrading microbial agent was used to ferment, the total biogas production increased by 72% comparing to the control. The content of methane could reach to 70.08%。

三孢布拉氏霉发酵产β-胡萝卜素的研究

本论文研究了利用三孢布拉氏霉(Blakeslea trispora)发酵产β-胡萝卜素的培养条件。主要包括：发酵培养基的确定，发酵条件的优化。还考察了发酵菌丝体中β-胡萝卜素的提取方法及薄层层析等。 首先研究了培养基成分对三孢布拉氏霉发酵产β-胡萝卜素的影响。确立了玉米淀粉作为碳源，黄豆粉（热榨）作为氮源，棉籽油作为植物油的发酵培养基配方，其成分为：玉米淀粉 3％，黄豆粉（热榨） 2％，棉籽油 3％，KH2PO4 0.2%，MgSO4·7H2O 0.2%，维生素B1 0.002％，pH值6.0。 其次，通过比较不同的发酵影响因子，分别得到最适的条件：如三孢布拉氏霉正负菌接种比例为1.3：0.7，培养基pH值为7.0（灭菌后），发酵促进因子为Triton X-100。并采用正交试验法，确定其最佳发酵条件为正负菌接种比例1.3/0.7，发酵培养基pH为7.0，在培养基中添加表面活性基Triton X-100 0.08％。使该菌株产β-胡萝卜素的量达到0.73g/L，较初始发酵条件提高了3.3倍。 研究中还找到一个简便有效的对β-胡萝卜素的提取方法，选用盐酸-热处理法进行细胞破壁，并选用沸程为60～90℃的石油醚进行萃取。 用三孢布拉霉菌丝体内类胡萝卜索的石油醚提取液点样于硅胶G板，以丙酮：石油醚（5：95）为展开剂能将β-胡萝卜素与其它类胡萝卜索分离。该方法简便快速，并有一定实用价值。 The fermentative conditions of β-carotene by Blakeslea trispora have been investigated. These conditions include fermentation medium, the optimization of some fermentation factor. The extracting methods and the TLC of carotenoids were also researched. Firstly, the effects of composition of fermentation medium on the yield of β-carotene were studied. the results showed that the best fermentation medium was corn starch 3％，soybean power 2％，cottonseed oil 3％，KH2PO4 0.2%，MgSO4·7H2O 0.2%，vitamin B1 0.002％，pH value 6.0. Secondly, through compared some factors, such as different proportion of plus and minus strains, pH value, nonionic surfactants, respective best values have been obtained. The best proportion of plus and minus strains is 1.3:0.7, pH value of fermentation medium (sterilized) is 7.0, fermentation accelerant which acts as surfactants is Triton x-100. Farther on, the fermentative conditions were optimized through orthogonal experiment, the optimization showed that proportion of plus and minus strains is 1.3:0.7，pH value is 7.0, content of Triton x-100 is 0.08％. And the yield of β-carotene reached 0.73g/L, which was up to 3.3 times through the fermentation. In the extracting study, it has showed hydrochloric acid-heat treatment is a simple, convenient and effective extracting methods is which was used to destroy the cell wall, and the extracting organic solvent is petroleum ether whose boiling range is 60~90 ℃. In the TLC experiments, extracting contents in the petroleum ether were spotted in the silicagel plate, and the mixed liquor of acetone and petroleum ether (5：95) is developping agent, which can distinguish β-carotene from other carotenoids. It is a simple and quick technique.

功能菌剂的混合发酵研究

随着化工行业的发展，大量有毒有害难降解有机物随工业废水的排放进入环境，这些物质能够在环境中长期存在、积累和扩散，通过食物链对动植物的生存及人类的健康造成不良影响。本文以苯酚、对氯硝基苯、氯苯和十六烷为模拟污染物，以前期研制的功能菌剂为对象，经过紫外线线诱变筛选出优于出发菌株的功能菌，对诱变后功能菌的理化性能进行了研究，对菌种进行了鉴定，在此基础上，就其相互之间的微生态关系进行研究，为混合发酵提供理论基础，并就其最佳发酵条件及发酵参数进行了研究，最后对发酵产品的性能进行了检测。目前，国内外有关功能菌剂的研究还存在多方面的不足，主要包括：①由于多菌种混合发酵过程较为复杂，各菌之间存在复杂的相互作用，影响因素较多，关于菌种之间的相互关系研究得很少，环境功能菌剂的发酵方法大多采用单独发酵后混合的方式。单独发酵对原材料、设备和能源的利用率较低，对于多菌种制剂发酵，在设备、能源和原材料的方面造成的浪费更大，将会大幅增加菌剂的生产成本，影响多菌种功能菌剂的发展；②功能菌剂生产过程的质量控制方面研究得较少；③功能菌剂产品的稳定性、抗冲击性能研究得较少，对环境微生物制剂的研究主要集中在菌种选育和培养条件优化方面。 通过本论文研究，得到以下主要结论。 （1）在紫外线诱变处理中，用紫外线对发生一定程度退化的出发菌株进行诱变处理后，六株具有高效降解性能的菌株被筛选出来，诱变筛选出的菌株形态和ERIC-PCR指纹图谱与出发菌株相比发生了明显改变；而且诱变后的菌株对目标难降解底物的降解能力均得到改善，其中，FPN、FCB、F14、FEm对目标底物的降解率提高了20%以上；诱变后菌株经过7次连续传代接种后，对目标难降解底物的降解率无显著变化，具有一定的遗传稳定性。并对诱变后的功能菌进行了初步的鉴定，这6株菌都分别是芽孢杆菌。 （2）对诱变后的功能菌相互之间的微生态关系进行了研究，通过抑菌实验、生长量以及基质消耗量的比较，确定它们之间的生长关系是无害共栖关系，可以进行混合发酵。 （3）对该功能菌剂进行发酵培养条件研究，结果表明发酵培养基的最佳成分（g/L）：葡萄糖 31.0g/L、玉米粉10.0g/L、磷酸氢二钾1.0g/L、硫酸铵1.1g/L、硫酸镁0.55g/L。通过研究不同的培养条件对菌体生长和降解性能的影响，确定了最佳培养条件：培养基初始pH7.5；最适温度32℃；培养基装液量125mL（250 mL三角瓶），以及培养时间对降解性能的影响，培养20 h的产物对降解最为有利。通过研究添加不同目标污染物对菌体生长和降解性能的影响，确定了添加目标污染物的最佳量以及最佳时间：苯酚投加量：1.125 g/L，对氯硝基苯投加量：0.1 g/L；最佳投加时间为发酵培养开始后4 h。 （4）以摇瓶分批发酵最优条件为基础，对FPN、F10、FCB、FNa、F14 和 FEm进行了摇瓶分批发酵试验。以摇瓶分批发酵试验数据为依据，对功能菌剂分批发酵动力学进行了研究，建立了菌体生长和基质消耗的动力学模型，拟合模型能较好的反映功能菌剂分批发酵过程。 （5）功能菌剂和活性污泥协同作用，可以提高系统的生物降解能力，功能菌剂投加量为2%，新鲜活性污泥3500 mg/L，降解24 h条件下，功能菌剂和活性污泥的协同作用对COD的去除率和对照组相比，最多的提高了36.8%。功能菌剂和活性污泥协同作用以及活性污泥的单独作用，其生物降解过程均符合一级反应动力学过程，功能菌剂和活性污泥协同作用的生物降解动力学方程为：，相关系数97%。采用SBR运行方式，引入功能菌剂的SBR系统明显能够改善和提高生物降解的效率。与仅有活性污泥的系统相比，系统对COD的平均去除率可以提高27.1%，同时，系统的耐负荷冲击以及耐毒害冲击的性能比仅有活性污泥的SBR系统强，特别是负荷冲击对引入功能菌剂的SBR系统影响很小。仅有活性污泥的SBR系统经过负荷冲击和毒害冲击之后，不能恢复到冲击之前的水平，而且系统有效作用时间的周期比引入功能菌剂的SBR系统相比大大缩短，而引入功能菌剂的SBR系统处理效果较为稳定，恢复能力很强。 Along with the development of industries, many recalcitrant organic chemicals have been discharged into natural environments together with wastewaters and can exist in waters, soil and sediments for a long time without degradation. These haz-ardous substances, their byporducts and metabolizabilities can be highly toxic, mu-tagenic and carcinogenic, thereby threatening animals, plants and human health through food chain. Consequently the removal of these compounds is of significant interest in the area of wastewater treatment. In this dissertation, the phenol, hydro-quinone, chlorobenzene and hexadecane treated as the model pollutants, the func-tional microorganism agent was used as the starting strains, they treated with ultra-violet light, and then the mutant strains with high degradation ability were screened out and identified primarily, the relationship between these stains were studied, the medium composition and fermentation conditions were optimized, the degradation ability of the fermented production was tested. The literature survey indicates that the study of the microorganism agent is far from complete and more information is re-quired on following problems. 1, Because of the complexity of relationship in mixed fermentation and the complicated factors, the study is hardly to process.2, There is a lack of information on the quality control of the producing process .3, And there is a lack of information on the stability about the microorganism agent. In this dissertation, the main results of the present study could be summarized as follows: (1)The degenerate starting strains were treated with the ultraviolet light, and six mutant strains with high biodegradation ability were screened out by using the me-dium with selective pressure of model pollutants. The mutant strains had great changes in colonialmorphology and ERIC-PCR fingerprinting. And the mutant strains got obvious advantages over the starting strains in degradation ability and over 20% improvement of removal rates was achieved for FPN、FCB、F14 and FEm. The de-gradation ability of the mutant strains was stable after seven generations. After that, the mutant strains were primarily identified as bacillus respectively. (2) The relationship between these mutant strains was studied. By the compari-son of antibiosis effect, biomass and consumption of substrate, the relationships were neutralism and they could be mixed fermented. (3) The optimized cultivation conditions were as follows: glucose 31.0 g/L, corn power 10 g/L, K2HPO4 1.0 g/L, (NH4)2SO4 1.1 g/L, MgSO4 0.55 g/L, initial pH7.5, temperature 32℃, working volume 125 mL/250 mL, and cultivation time 20h (con-sidering the time effect on degradation ability), adding pollutants phenol (1.125 g/L) and hydroquinone (0.1 g/L) into the broth at 4 h after cultivation. (4) Based on the above optimum condition, the batch fermentation was per-formed with strains FPN, F10, FCB, FNa, F14 and FEm in shake flask. The batch fermentation kinetics was studied based on the experimental data. Two kinetic models were constructed which could reflect the regularity of growth and substrate consump-tion in the process of batch fermentation. (5) The co-operation of functional microorganism agent and activated sludge could raise biodegradation of system by adding some microorganism agent and 3500 mg/L fresh activated sludge. Bioaugumentation by the addition of high effective deg-radation culture enhanced the treatment effect of SBR system and the COD removal rate was increased by 20%-36.8%. Its biodegradation matched first-order dynamical reaction equation, and the reaction equation was ln0.2327.391ct=−+. The micro-organism agent had the effect of optimization to activated sludge micro-ecosystem. The SBR system adding 2% microorganism agent, the average COD removal rate of that was increased by 27.1% and stronger anti-shock ability to load and toxicant were achieved (compared with SBR system just adding activated sludge). Especially the load-shock has barely effect to the SBR system adding microorganism agent. After the load and toxicant shock, the SBR system just adding activated sludge couldn’t come back to original level and the activated sludge micro-ecosystem was frustrated. The applying of microorganism agent increased biological activity and system’s re-sistance ability to load shock and toxicant shock.

克拉维酸产生菌的诱变育种与发酵工艺优化研究

以克拉维酸产生菌棒状链霉菌Streptomyces clavuligerus CCRC11518（ATCC 27064）III50为出发菌株, 首先比较各种物理和化学诱变剂处理对其克拉维酸生物合成的影响, 确定了亚硝基胍为棒状链霉菌诱变育种的诱变剂及其处理剂量: 2mg/ml、40min. 经浓度为2mg/ml的亚硝基胍处理40min后, 采用新颖理性化筛选方法, 通过逐步筛选自身代谢产物抗性突变株、克拉维酸抗性突变株和链霉素抗性突变株, 最终得到一株克拉维酸高产菌VI118(效价633μg/ml), 其克拉维酸效价是出发菌株(效价377μg/ml)的167.9%. 该高产突变株在琼脂斜面培养基上连续传接10代, 克拉维酸效价保持稳定. 通过单因子和多因子摇瓶正交试验, 对高产菌株VI118的发酵条件进行了研究, 确定最佳发酵条件: 甘油60g, 水解植物蛋白 60g, KH2PO4 0.5 g, 玉米浆 7.5g, MnSO4•H2O 0.34g, MgSO4•7H2O 0.99g, FeSO4•7H2O 0.56g, 蒸馏1000ml, pH 7.0, 发酵培养基装量20ml/250ml三角瓶, 接种量10％, 培养温度28ºC, 220r/min摇床培养72h后测定效价. 在最佳发酵条件下克拉维酸效价达到651μg/ml, 同时把初始发酵培养基的昂贵成分替换为廉价的工业原料. 通过摇瓶分批补料试验, 得到最佳补料物质和补料方式：在上述最佳发酵条件下, 分别在发酵培养48h、56h、64h、72h时补加4ml无菌水, 80h发酵结束, 克拉维酸效价达到905μg/ml. 在不增加原料成本的情况下通过摇瓶补料方式克拉维酸效价为未补料的139.0％, 总产量为未补料的264％. By a novel rational screening method, mutant Streptomyces clavuligerus CCRC11518（ATCC 27064）III50（titres 377μg/ml）, as the clavulanic acid-producing parent strain, was treated by NTG (2mg/ml) for 40min, and the self-generated metabolites resistant mark, the clavulanic acid resistant mark and the streptomycin resistant mark were added step by step. Finally, the mutant VI118（titres 633μg/ml）with the three marks was obtained. The clavulanic acid productivity of this mutant was increased by 167.9% compared with the parent strain. After reproducing 10 generations on the agar medium slant, the productivity of this mutant was stable. The optimum fermentation conditions were established as followings: glycerol 60g, acid hydrolyzed vegetable protein 60g, KH2PO4 0.5g, corn steep liquor 7.5g, MnSO4•H2O 0.34g, MgSO4•7H2O 0.99g, FeSO4•7H2O 0.56g, distilled water 1 liter, pH 7.0, 20ml in 250ml shake-flask, inoculation 10%(v/v), fermentation temperature 28ºC, rotation speed 220 r/min, time 72h. The clavulanic acid productivity was 651μg/ml, while used the low-priced industrial raw materials. After studying on fed-batch in the shake-flask, the optimum fed-batch manner was obtained: under optimum fermentation conditions, at 48h, 56h, 64h and 72h, adding 4ml distilled water into each flask, fermentation ending at 80h. The clavulanic acid productivity was increased by 139% compared with no fed-batch, meanwhile the total yield was increased by 264%.

非粮原料燃料乙醇发酵关键技术的研究

生物质燃料乙醇是一种高度清洁的交通液体燃料，是减少温室气体排放，缓解大气污染的最佳技术选择。以非粮原料生产燃料乙醇可以在进行能源生产的同时保证粮食安全，有利于产业的可持续发展。在众多的非粮原料中，甘薯是我国开发潜力最大的生物质能源作物之一。我国占世界甘薯种植总面积和产量的90％。同时，甘薯的单位面积燃料乙醇产量远大于玉米和小麦。其成本是目前酒精中最低廉的，因此利用甘薯生产乙醇是发展生物质燃料乙醇的首要选择。目前采用薯类全原料主要采用分批发酵生产乙醇，其技术水平低，发酵强度低，一般在0.7－2.5g/（L•h），乙醇浓度低，甘薯发酵乙醇为6－8％(v/v)，能耗高，环境负荷大，污染严重。针对上述问题，本文从菌株选育、原料预处理、中试放大、残糖成分分析等方面进行研究。 为了研究乙醇发酵生产规模扩大过程中，大型发酵罐底部高压条件下，CO2对酵母乙醇发酵的影响，我们通过CO2 加压的方法进行模拟试验，研究结果表明，发酵时间随压强的升高而逐渐延长，高压CO2 对乙醇发酵效率影响不大，在0.3 MPa 以下时，发酵效率均可达到90%以上。高压CO2 对发酵的抑制作用是高压和CO2 这两个因素联合作用的结果。高压CO2 条件下，酵母胞外酶和胞内重要酶类的酶活均表现出特征性。0.2 MPa 下，酶活性的变化趋势和0.1 MPa 条件下的较为一致。而0.3 MPa 下的酶活变化趋势与0.4 MPa 下的酶活更为接近。通过全基因表达分析发现在CO2 压力为0.3 MPa 下，乙醇发酵途径中多个基因表达量下调，同时海藻糖合成酶和热激蛋白基因表达量上调。 筛选耐高温的乙醇酵母菌株能够解决糖化温度和发酵温度不协调的矛盾，实现真正意义上的边糖化边发酵。高温发酵还能够降低发酵时的冷却成本，实现乙醇的周年生产。本研究筛选出一株高温发酵菌株Y-H1，进而我们对该菌株的胞外酶和胞内乙醇代谢重要酶类的酶活性进行了分析。结果表明Y-H1 能够在40 ℃条件下正常进行乙醇发酵，发酵33h，最终乙醇浓度达到10.7%（w/w），发酵效率达到90%以上。同时发酵液最终pH 在3.5 左右，显示菌株具有一定的耐酸性能力。同时观察到40 ℃下，菌株的胞外酶和胞内乙醇代谢重要酶类的酶活性发生了变化，乙醇发酵途径中关键酶基因表达下调，而海藻糖合成酶与热激蛋白基因表达量上调，这些结果为进一步研究酵母菌耐热调控机理提供了依据。 糖蜜是一种大规模工业生产乙醇的理想原料，本研究利用选育高浓度乙醇发酵菌株结合配套的发酵稳定剂，研究了糖蜜高浓度乙醇发酵情况。结果表明采用冷酸沉淀预处理糖蜜溶液，采用分批补料的发酵方式，乙醇浓度最高达到了10.26% (w/w)，发酵时间为42 h。同时观察到在糖蜜发酵中，乙醛含量与乙醇浓度存在一定的相关性。 快速乙醇发酵对于缩短乙醇生产周期、降低乙醇生产成本、减少原料腐烂损失具有重要意义。本研究诱变和筛选得到了一株快速乙醇发酵菌株10232B。在优化后的发酵条件下，采用10L 发酵罐进行分批乙醇发酵，经过18h,乙醇的最终浓度达到88.5g/L,发酵效率93.6%，平均乙醇生产速度达到4.92 g/L/h。此菌株在保持较高乙醇生产浓度的同时，拥有快速生产乙醇的能力，适合作为快速乙醇发酵生产菌种。 由于鲜甘薯具有粘度大的特点，传统液化糖化处理很难在短时间内充分糖化原料；高粘度的醪液也难以进行管道输送，容易堵塞管路；同时，也会降低后续的乙醇发酵效率。 本文采用了快速粘度分析法对鲜甘薯糊化粘度特性进行了分析，进而对预处理条件进行了研究，在最佳预处理条件下，糖化2h 后，醪液葡萄糖值最高可达99.3，粘度4.5×104 mPa.s，而采用传统糖化工艺，醪液DE 值仅为85.8，粘度大于1.0×105 mPa.s。 此预处理方法也可用于快速糖化不加水的醪液。后续的乙醇发酵试验表明，通过此预处理方法获得的糖化醪液对乙醇发酵无负面影响。 在前期已实现了实验室水平的鲜甘薯燃料乙醇快速乙醇发酵基础上，进一步将发酵规模扩大到500L，在中试水平上对甘薯乙醇发酵进行了研究。结果表明在500L 中试规模，采用边糖化边发酵（SSF）工艺，在料液比为3∶1，发酵醪液最高粘度为6×104mPa.s 条件下，发酵37h，乙醇浓度达到了12.7%（v/v），发酵效率91%，发酵强度为2.7 g/（L•h）。与目前国内的薯类乙醇发酵生产技术水平具有明显的优越性。 为研究甘薯、木薯乙醇发酵中残糖的组成，采用了高效液相色谱—蒸发光散射检测法，对乙醇发酵残糖进行了分析。结果表明，甘薯、木薯乙醇发酵残糖均为寡聚糖，主要由葡萄糖、木糖、半乳糖、阿拉伯糖和甘露糖构成。随着发酵时间延长，寡聚糖中的葡萄糖、半乳糖、甘露糖可被缓慢的水解释放。提高糖化酶量仅在一定程度上降低残糖，过量的糖化酶反而会导致残糖增加。同时发现3, 5-二硝基水杨酸法不能准确测定甘薯、木薯乙醇发酵中的残总糖含量。进一步筛选了两株残糖降解菌株，对甘薯乙醇发酵残糖的降解利用率均达到了40%以上，而且还能显著降低发酵醪液粘度。经形态学和rRNA ITS 序列分析，确定这两株菌分别属于为木霉属和曲霉属黑曲霉组。 通过对以甘薯原料为代表的非粮原料发酵技术研究开发，以期形成乙醇转化率高，能耗低，生产效率高、季节适应性好，原料适应性广，经济性强，符合清洁生产机制的燃料乙醇高效转化技术，为具有我国特色的燃料乙醇发展模式提供技术支持。 Sweet potato is one of the major feedstock for the fuel ethanol production in China. The planting area and the yield in China take 90% of the world. Sweet potato is an efficient kind of energy crops. The energy outcome per area is higher than corn or wheat. And the manufacture cost of ethanol is the lowest, compared with corn and wheat. So sweet potato is the favorable crop for the bioethanol production in China. However, the low-level fermentation technology restricts the development of ethanol production by sweet potato, including slow ethanol production rate, low ethanol concentration and high energy cost. To solve these problems, we conducted research on the strain breeding, pretreatment, pilot fermentation test and residual saccharides analysis. To study the impact of hyperbaric condition at bottom of the large fermentor on yeast fermentation, high pressure carbon dioxide (CO2) was adopted to simulate the situation. The results showed that the fermentation was prolonged with the increasing pressure. The pressure of CO2 had little impact on the ethanol yield which could reach 90% under the pressure below 0.3 MPa. The inhibition was combined by the high pressure and CO2. Under the high CO2 pressure, the extracellular and important intracellular enzyme activities were different from those under normal state. The changes under 0.1 MPa and 0.2 MPa were similar. The changes under 0.3 MPa were closer to those under 0.4 MPa. The application of thermotolerance yeast could solve the problem of the inconsistent temperature between fermentation and saccharificaton and fulfill the real simultaneous saccharification and fermentation. And it could reduce the cooling cost. A thermotolerance strain Y-H1 was isolated in our research. It gave high ethanol concentration of 10.7%（w/w）at 40 ℃ for 33 h. The ethanol yield efficiency was over 90%. At 40 ℃, the extracellular and important intracellular enzyme activities of Y-H1 showed the difference with normal state, which may indicate its physiological changes at the high temperature. Molasses is another feedstock for industrial ethanol production. By our ethanol-tolerance strain and the regulation reagents, the fermentation with high ethanol concentration was investigated. In fed-batch mode combined with cold acid deposition, the highest ethanol concentration was 10.26% (w/w) for 42h. The aldehyde concentration in fermentation was found to be related to ethanol concentration. The development of a rapid ethanol fermentation strain of Zymomonas mobilis is essential for reducing the cost of ethanol production and for the timely utilization of fresh material that is easily decayed in the Chinese bioethanol industry. A mutant Z. mobilis strain, 10232B, was generated by UV mutagenesis. Under these optimized conditions, fermentation of the mutant Z. mobilis 10232B strain was completed in just 18 h with a high ethanol production rate, at an average of 4.92 gL-1h-1 per batch. The final maximum ethanol concentration was 88.5 gL-1, with an ethanol yield efficiency of 93.6%. This result illustrated the potential use of the mutant Z. mobilis 10232B strain in rapid ethanol fermentation in order to help reduce the cost of industrial ethanol production. As fresh sweet potato syrup shows high viscosity, it is hard to be fully converted to glucose by enzymes in the traditional saccharification process. The high-viscosity syrup is difficult to be transmitted in pipes, which may be easily blocked. Meanwhile it could also reduce the later ethanol fermentation efficiency. To solve these problems, effects of the pretreatment conditions were investigated. The highest dextrose equivalent value of 99.3 and the lowest viscosity of 4.5×104 mPa.s were obtained by the most favorable pretreatment conditions, while those of 85.8 and over 1.0×105 mPa.s was produced by traditional treatment conditions. The pretreatment could also be applied on the material syrup without adding water. The later experiments showed that the pretreated syrup had no negative effect on the ethanol fermentation and exhibited lower viscosity. The fuel ethanol rapid production from fresh sweet potato was enlarged in the 500L pilot scale after its fulfillment on the laboratory level. The optimal ratio of material to water was 3 to 1 in 500L fermentor. With low-temperature-cooking (85 ℃) using SSF, the Saccharomyces cerevisiae was able to produce ethanol 97.44 g/kg for 37h, which reached 92% of theoretical yield. The average ethanol production rate was 4.06 g/kg/h. And the maximum viscosity of syrup reached 6×104mPa.s. The results showed its superiority over current industrial ethanol fermentation. The compositions of the residual saccharides in the ethanol fermentation by sweet potato and cassava were analyzed by high performance liquid chromatography coupled with evaporative light-scattering detector. The results showed that all the residual saccharides were oligosaccharides, mainly composed of glucose, xylose, galactose, arabinose and mannose. The glucose, galactose and mannose could be slowly hydrolyzed from oligosaccharides in syrup during a long period. To increase the glucoamylase dosage could lower the residual saccharides to a certain extent. However, excess glucoamylase dosage led to more residual saccharides. And the method of 3, 5-dinitrosalicylic acid could not accurately quantify the residual total saccharides content. Two residual saccharides degrading strains were isolated, which could utilize 40% of total residual saccharide and lower the syrup viscosity. With the analysis of morphology and internal transcribed spacer sequence, they were finally identified as species of Trichoderma and Aspergillus niger.

组合白腐真菌预处理木质纤维素原料的研究

木质纤维素原料种类多、分布广、数量巨大，通过燃料乙醇生产技术、厌氧沼气发酵技术将其转化成乙醇、沼气等二次能源，一定程度上可以缓解化石能源的不断消耗所带来的能源危机，也解决了农林废弃物引起的环境污染问题。其中以木质纤维素原料生产燃料乙醇，还可以避免以淀粉类和糖类原料生产燃料乙醇时带来的“与人争粮”等一系列问题。因此具有重要的经济效益、环境效益和社会效益。 然而，木质纤维素原料结构致密，木质素包裹在纤维素、半纤维素外围，导致其很难被降解利用，必须进行适当的预处理，去除木质素，打破原有的致密结构，利于原料的后续利用。因此，预处理成为木质纤维素原料能源化利用的关键。而目前预处理环节的费用过于昂贵，于是寻找一种高效、低成本的预处理方法是当今研究的热点。 本论文采用组合白腐真菌对木质纤维素原料进行生物预处理研究，与其他物理化学法相比，该法有着专一性较强、反应温和、不造成环境污染、成本低等优势。白腐真菌主要通过分泌木质素降解酶对木质素进行降解，从而破坏原料的致密结构，提高后续利用效率。所以木质素降解酶酶活的高低是影响原料预处理效果的一个关键因素。于是本论文首先通过将白腐真菌进行组合的方式提高木质素降解酶（漆酶，Lac）酶活；接着对组合菌的菌株相互作用机理进行研究，阐明组合菌Lac 酶活提高的原因，为菌株组合提高Lac 酶活这种方法的应用提供理论依据，同时也为后续组合白腐真菌预处理木质纤维素原料提供指导；进一步采用固态发酵和木质素降解酶两种方式对木质纤维素原料进行预处理研究，最大化去除木质素成分，破坏原料的致密结构；最终对预处理后原料的酶解糖化进行初步研究，为原料后续的能源化应用奠定基础。具体研究结果如下： （1） 以实验室保存的三株主要分泌Lac 的白腐真菌为出发菌株，筛选得到一组Lac 酶活明显提高的组合菌55+m-6，其中菌株55 为Trametes trogii sp.，m-6 为Trametes versicolor sp.，组合后Lac 酶活较单菌株分别提高24.13倍和4.07 倍。组合菌的最适产酶条件为pH 6.5、C/N 16:1、Tween 80 添加量为0.01%，在该条件下组合菌的Lac 酶活峰值比未优化时提高4.11倍。 （2） 对组合菌55+m-6 菌株间相互作用机理进行研究，发现菌株之间不存在抑制作用；平板培养时，菌丝交界处Lac 酶活最高并分泌棕色色素；液体培养时，菌株m-6 对组合后Lac 酶活的提高起着更为重要的作用：菌株m-6的菌块、过滤灭菌胞外物以及高温灭菌胞外物均能明显刺激菌株55 的Lac产生；菌株55、m-6 进行组合后，同工酶种类未发生增减，但有三种Lac同工酶浓度有所提高；对菌株胞外物进行薄层层析和质谱分析，结果表明组合前后菌株胞外物中各物质在浓度上存在较大的变化。推测组合菌Lac酶活的明显提高，主要是由于菌株m-6 胞外物中的一些物质能刺激菌株55 分泌大量Lac 进行代谢，且这些刺激物质并非菌株m-6 特有，菌株55自身也可以代谢生成，但是适当的浓度才能刺激Lac 的大量分泌。 （3） 将组合菌55+m-6 用于固态发酵预处理木质纤维素原料，发现其对玉米秆的降解程度最大，在粉碎度40 目、含水率65%的最优处理条件下，处理至第15d，秸秆失重率为41.24%，其中木质素、纤维素、半纤维素均有降解，且Lac 和纤维素酶（CMC）酶活以及还原糖量均达到峰值。 （4） 对玉米秆进行木质素降解酶预处理，发现Lac/1-羟基苯并三唑（HBT）系统对玉米秆木质素的降解效果最好，在最优处理条件时，即HBT 用量0.2%、处理时间1d、Lac 用量50U/g，木质素降解率可达12.60%。预处理后玉米秆的致密结构被破坏，比表面积增大，利于后续酶与纤维素、半纤维素成分的结合。 （5） 对预处理后的玉米秆进行酶解糖化，其中组合菌固态发酵预处理后玉米秆的糖化率比对照高4.33 倍；Lac/HBT 系统预处理后玉米秆的糖化率比对照高2.99％，糖化液中主要含有木糖、葡萄糖两种单糖。 There are many kinds and large quantities of lignocellulosic biomass widely distributed on the earth. They can be converted into secondary energy such as fuel ethanol, biogas, et al., which can relieve the energy crisis caused by consumption of fossil energy resources and solve the problem of environmental pollution caused by agriculture and forestry waste. Meanwhile, the production of fuel ethanol from lignocellulosic biomass can ensure food supply to human kind instead of starch- and sugar-containing raw materials. So the energy conversion of lignocellulosic biomass contributes considerable economic, environment and social benefits. However, lignocellulosic biomass has the compact structure, in which lignin surrounds cellulose and hemicellulose, so it must be pretreated before energy usage and pretreatment is one of the most critical steps in the energy conversion of lignocellulosic biomass. At present, the cost of pretreatment is too expensive, so looking for an efficient and low-cost pre-treatment method is one of recent research hot spots. In this research, combined white rot fungi pretreatment method was used, which had some advantages in low cost, high specificity, mild reacting conditions and friendly environmental effects compared with the other physical and chemical methods. White rot fungi secrete lignin degrading enzymes to degrade the content of lignin and damage the contact structure of lignocellulosic biomass, so the activity of the lignin degrading enzymes is the key factor to the degradation effect of raw materials. Firstly, the combined fungi with high laccase activity were screened; secondly, the interaction mechanism between strains was studied, and the cause of higher laccase activity after strains combination was also preliminary clarified; under the guidance of the mechanism, lignocellulosic biomass was pretreated by the combined fungi; lastly, the enzymatic hydrolysis of pretreated lignocellulosic biomass was also preliminary studied; all of the researches could lay the foundation for the energy application of lignocellulosic biomass. The specific research results were as follows: (1) The combined fungi 55+m-6 with significant higher laccase activity were screened from the three white rot fungi stored in our lab which mainly secreted laccase. Strain 55 and strain m-6 were Trametes trogii sp. and Trametes versicolor sp., respectively. The laccase activity of combined fungi was 24.13 and 4.07-fold than strain 55 and strain m-6, respectively. The optimized condition for laccase production of the combined fungi in liquid medium was pH 6.5, C/N 16:1 and Tween 80 0.01%. In this optimized condition, the laccase activity of combined fungi was 4.11-fold higher comparing with which in non-optimized medium. (2) The interaction mechanism between strain 55 and strain m-6 was further studied, and no inhibition effect was observed. Brown pigment was secreted on the junction of the two strains on the plate, where the highest laccase activity was detected. Strain m-6 was much important to boost laccase activity of combined fungi in liquid medium, and strain 55 was stimulated by fungal plug, filter sterilized extracellular substances and high temperature sterilized extracellular substances of strain m-6 to produce laccase. The types of laccase isozymes did not change after combining strain 55 and strain m-6, but the concentrations of three types increased. Mass Spectrometry and TLC analysis of extracellular substances of each strain showed that concentration of some substances considerably changed after strains were combined. It was supposed that the cause of higher laccase activity of combined fungi was mainly due to some extracellular substances of strain m-6 with the appropriate concentration which stimulated laccase secretion of strain 55 and generated not only by strain m-6 but also by strain 55. (3) Combined fungi 55+m-6 were used to lignocellulosic biomass pretreatment with the type of solid-state fermentation. The highest degree of degradation of corn straw was obtained, including the rate of weight loss was 41.24% and the lignin, cellulose and hemicellulose were degraded partially under the optimized condition of 40 mesh, 65% water content on 15th day. Laccase, CMCase activities and content of reducing sugar reached the maximum value on that day. (4) Lignin degrading enzymes from combined fungi 55+m-6 were used for corn straw pretreatment. The most remarkable degradation of lignin in corn straw with Lac/1-hydroxybenzotriazole (HBT) system was observed, and the 12.60% lignin degradation was obtained under the optimized condition of 0.2% HBT, 50 U/g laccase for 1 d. After pretreated by Lac/HBT, the tight structure of corn straw was demolished and specific surface area increased, which had advantages for accessible of enzyme to cellulose and hemicellulose. (5) The corn straws pretreated by combined fungi 55+m-6 with the type of solid-state fermentation and Lac/HBT were used for enzymatic hydrolysis, and the saccharification rates of each pretreatment type were 4.33 times and 2.99% higher than CK, respectively. The enzymatic hydrolysis liquid of corn straw pretreated by Lac/HBT mainly contained xylose and glucose.

一株丝状真菌对半纤维素利用的初步研究

本文筛选出一株能利用木糖产乙醇的丝状真菌Z7，对其利用木糖和半纤维素水解产物产乙醇的发酵条件进行了研究，并对Z7 利用玉米芯产木聚糖酶的条件进行了优化。全文分为三部分： 第一部分：目标微生物筛选、纯化及系统发育分析。以木糖为唯一碳源，采用梯度稀释和平板化线法从高温、中温酒曲中分离到16 株能利用木糖良好生长的丝状真菌；通过发酵试验复筛，获得一株能产乙醇的丝状真菌Z7；综合形态学和ITS 序列分析，初步鉴定为Aspergillus flavus。 第二部分：Z7 的乙醇发酵条件研究。以木糖为碳源，通过单因素试验确定最佳氮源和发酵温度；通过正交试验及SPSS 软件分析得到了不同N、P、K 成分对乙醇、残糖和菌体干重的影响。获得最佳的发酵条件为：（g/L）木糖50，尿素1, NH4NO3 1, K2HPO4 2 , KCl 0.5 , MgSO4.7H2O 0.5 , NaNO3 1 , pH 自然，培养温度33 ℃。以玉米芯半纤维素稀酸水解液为底物进行乙醇发酵，根据稀酸水解的单糖释放量和乙醇产量，确定115 ℃，1 h 为最佳玉米芯预处理条件；结合最佳发酵条件，添加1 g/L 的吐温20 能获得最大的乙醇浓度8.31 g/L。因此，Aspergillus flavus Z7 能利用半纤维素水解产物产乙醇，其中木糖的利用率80%以上。 第三部分：Z7 利用玉米芯产木聚糖酶条件优化。Aspergillus flavus Z7 在具有产乙醇能力的同时还具有产木聚糖酶的能力。本文通过单因素和正交试验得到最佳产酶培养基组分为：(g/L)玉米芯20，尿素2, 酵母膏2.5, K2HPO4 5，NaNO31, MgSO4.7H2O 1。单因素试验表明，用纱布代替塑料布密封摇瓶封口能显著提高产酶量；Z7 在碱性条件下具有更强的产酶性能。在最优条件下发酵，能产生最大木聚糖酶活122.23IU/mL。通过薄层分析，验证了Z7 产生的木聚糖酶具有水解木聚糖生成木糖及木寡糖的能力。 A strain of filamentous fungus which can produce ethanol by using the xylose was isolated in this research. The ethanol fermention conditions from xylose and dilute-acid hydrolyzate of the corn core were studied. The conditions of xylanase production by Z7 were also optimized. The paper involved three parts. Part1: Isolation, purification and phylogenetic analysis of the microbe. By using xylose as the single carbon source and the pla te streaking method, several filamentous fungi were isolated from the wine starter; through the fermentation test, a filamentous fungus Z7 which can produce ethanol was further recognized; furthermore, according to the morphologic observation and ITS seque nces analysis, Z7 was identified as Aspergillus flavus at the first step. Part2: Research on the condition of ethanol fermentation by Z7. By single factor experiment, the optional nitrogen resource and temperature of the fermentation were fixed; meanwhile, through the orthogonal array tests and the analysis of statistic software SPSS, the optional component of the culture medium and the fermentation condition were organized as follows: (g/L) xylose 50, urea 1, NH4NO3 1, K2HPO4 2, KCl 0.5 , MgSO4.7H2O 0.5, NaNO31, pH nature, temperature 33℃. Based on these optimal parameters, the fermentation of dilute-acid hydrolyzate of the corn core was carried on by Z7. According to the quantities of released sugar monomers and content of the ethanol, 115℃ in 1h is the best pretreatment condition; the maximal ethanol content can be obtained when 1g/L Tween 20 was added to. Therefore, the filamentous fungus Aspergillus flavus can use the hydrolysate of hemicellulose to produce ethanol, and the rate of xylose utilization was over 80%. Part3: Optimization of Z7’s xylanase producing condition from corn core. Aspergillus flavus Z7, which can utilize xylose or the hydrolysate of hemicellulose to produce ethanol, also had the ability of xylanase production. The optional component of the culture medium were fixed by the single factor experiment and the orthogonal array tests, and they were organized as follows: (g/L) corn core 20, Urea 2, Yeast extract 2.5, K2HPO4 5, NaNO31, MgSO4.7H2O 1; it was testified by the single factor experiment that sealing the shaking flasks with pledget other than plastic paper can obviously increase the xylanase activity; moreover, Z7 showed better xylanase production ability when in the alkali environment. Under the optional fermentation condition, the maximal xylanase activity 122.23IU/mL was proved. Through the analysis of thin- layer chromatography (TLC), the ability of xylanase from Z7, which can hydrolyze xylan to xylose monomer and oligomer, was vividly displayed.

聚丙烯酰胺防治水土流失的效果

Field plots observations indicate that applying polyacrylamide to soil can reduce surface runoff by 18 4%～46 8%,decrease soil erosion by 13%～55%,and increase soil organic matter,alkali-hydrolyzable nitrogen,available phosphate,available potassium in different degrees compared with not application.In addition,applying polyacrylamide can also increase corn yield by 540 5kg·ha -1 ,and net income by 240 5ha.

Natural 13C abundance as a tracer for studies of soil organic matter dynamics

A method for measuring the long- and medium-term turnover of soil organic matter is described. Its principle is based on the variations of 13C natural isotope abundance induced by the repeated cultivations of a plant with a high 13C/12C ratio (C4 photosynthetic pathway) on a soil which has never carried any such plant. The 13C/12C ratio in soil organic matter being about equal to the 13C/12C ratio of plant materials from which it is derived, changing the 13C content of the organic inputs to the soil (by altering vegetation from C3 type into C4 type) is equivalent to a true labelling in situ of the organic matter. Two cases of continuous corn cultivation (Zea mays: δ13C = −12%.) on soils whose initial organic matter average δ13C is −26%. were studied. The quantity of organic carbon originating from corn (that is the quantity which had turned-over since the beginning of continuous cultivation) was estimated using the 13C natural abundance data. After 13 yr, 22% of total organic carbon had turned-over, in the system studied. Particle size fractions coarser than 50μm on the one hand, and finer than 2μm on the other. contained the youngest organic matters. The turnover rate of silt-sized fractions was slower

土壤改良剂与氮肥配施对玉米生长及其养分含量的影响

采用盆栽试验研究了秸秆配方、废料配方和胶土配方3种改良剂与氮肥配施对玉米植株生长状况、生物量、叶绿素含量、全N及全P含量的影响。结果表明:3种改良剂与0.5 g/盆氮肥配施可以显著提高株高、茎粗、叶面积、地上地下生物量、叶绿素含量及植株全N含量,且以秸秆配方配施效果最佳,过量施用氮肥(1.0 g/盆)时,各指标与0.5 g氮肥水平下的值相比增加幅度甚小,茎粗和地下生物量甚至有下降的趋势。改良剂因素和氮肥因素对全P含量也有一定的影响,但二者交互作用对其并未产生显著性影响。因此,在施加改良剂的条件下可以适当地减少肥料的使用量,在满足植物体吸收利用前提下,既减少了养分投入和浪费,又减轻了对环境的污染。

新型土壤结构改良剂水分特性及其对玉米苗期的影响研究

试验采用室内研究的方法,探讨2种以环境废弃资源为主要原料的新型土壤改良剂的基本水分特性,验证其对玉米苗期的影响。试验结果表明,2种改良剂在不同溶液中溶胀度不同,PJG在蒸馏水中溶胀度最大,PFL则是在自来水中吸水能力最强。PFL的吸水速率要低于PJG,单位质量最大吸水量1.705,为PJG的46.9%。2种改良剂对玉米出苗率的影响不是很明显,但能显著地提高玉米苗期株高和叶面积,对苗期土壤水分的散失也起到了很好的抑制作用。2种改良剂都能明显提高玉米苗期水分利用效率,最优水平分别高于对照27.89%和58.99%。综合各方面结果,建议在玉米试验中使用PJG的最佳浓度为0.8%,PFL为0.05%。

利用城乡废弃资源提高土壤保水保肥功能

以生活炉渣、建筑废料、生物秸秆等城乡废弃资源为原料,制备一种面向节水农业的环保新产品———土壤扩蓄增容肥.实验结果表明:在棉花苗期,6种土壤扩蓄增容肥配方的节水效果较土对照高300倍,干物质积累增加4.77%~50.00%.6种配方的皮棉产量均比对照高,增产幅度为4.70%~14.25%,纤维物理性状有所改善.产量高低顺序依次是,玉米秸秆>小麦秸秆>生活炉渣>秸秆木炭>建筑废料>煤矸石>CK.利用城乡废弃资源生产的扩蓄增容剂,不仅能改良土壤物理和化学性状,更是棉花增产、优质、节水、降低生产成本的关键技术措施之一,具有显著的生态效益、社会效益和经济效益.