Feasibility study of biofuel production from freshwater fern, Azolla sp in Anzali Wetland

Production of bioethanol through acidic and enzymatic hydrolysis of aquatic Azolla sp., as a new source of bio-mass, has been performed, as a means to control increasing growth and reducing undesirable effects of this plant in Anzali lagoon. After sampling, drying and crushing, Azolla was hydrolyzed, using diluted acid and enzyme. Diluted acid hydrolysis was done using both autoclave and a high-pressure system (Batch Synth® Microwave synthesizer). The effects of temperature and time (in autoclave) and concentration of acid (in both) were compared. Cellubrix®, a ommercial cellulase source, was used for enzymatic hydrolysis process. The amounts of reducing sugars, glucose and furfural, released from hydrolyzate, were measured. To produce alcohol, Sacchromyces cerevisiae (to ferment sixcarbon sugars), Zygowilliopsis californica and Pichia stipitis (to ferment five-carbon and sixcarbon sugars) were used. Maximum amounts of glucose (4.83% w/w) and reducing sugars (14.15% w/w) were obtained using acid hydrolysis in autoclave. In the microwave oven, maximum glucose (5.04% w/w) and reducing sugars (13.27 w/w) were obtained at 180 and 200 °C, respectively. Under these conditions, maximum produced furfural was 1.54 g/L. The difference between amounts of furfural obtained from acid hydrolysis of Azolla in microwave oven compared to autoclave was statistically significant. Amounts of alcohol produced and its yields were 3.99 g/L and 33.13% for S. cerevisiae in 48 hours, 3.73 g/L and 30.45% for Pichia stipites in 48 hours, and 3.73 g/L and 30.45% for Z. californica in 24 hours after inoculation, respectively, with significant differences. Statistical comparison of results showed significant differences (P<0.05) in glucose production, at different conditions. Amounts of reducing sugars and glucose increased after optimization of levels of acid, time, and temperature. The overall optimum released sugar and glucose were obtained with 1.67% (w/v) acid using autoclave. Higher temperatures in microwave oven caused a significant increase (P<0.05) in furfural. Furfural severely inhibits fermentation. Hence, regarding the issues of energy consumption and time, amounts of inhibiting substances and sugar production, autoclave is found to be superior to the high temperature and pressure, generated in microwave oven, for hydrolyzing Azolla. Furthermore, given the amounts of Azolla in Anzali lagoon, it may be recommendable to use this plant as a biomass resource.

An assessment of handling and processing methods used for the shrimp fishery by-catch in Kalpitiya, Sri Lanka

The by-catch from the shrimp trawl fishery in Kalpitiya is mainly used for the production of dried fish, which provides an additional source of income for fishermen in the area. It has been observed that current handling practices along the value addition chain are responsible for the poor quality and low price of the end product. This study was aimed at identifying the shortcomings in such handling practices by fishermen and dried fish producers and assessing the quality of shrimp fishery by-catch along the processing chain in order to recommend more efficient utilization methods that will improve the quality of the end product. Fresh fish, dried fish and harbour water samples were tested for total coli forms, faecal coliforms, E. coli and Salmonella in order to assess their microbial quality: In addition, standard plate counts (SPC) of fish samples were also carried out. A survey was carried out from July-October 2006 at Kalpitiya, using a pre-tested questionnaire to collect information from individuals who have been engaged in dried fish processing. Average values obtained for freshly landed and dried fish respectively, were, SPC 9.88x10 super(5) CFU/g and 30.43x10 super(5) CFU/g, total coliforms 23.05 and 24.23 MPN/g and fecal coliforms 8.28 and 9.00 MPN/g. These values exceed the recommendations in the SL standards. A quarter of the landed fresh fish and 38% of dried fish from the producers were positive for E. coli and thus failed to show required end product quality. SPC of harbour water was 14.35x10 super(6) CFU/ml and all samples were found to be contaminated with E. coli. None of the fishermen and dried fish producers were satisfied with the quality of the end product. The reasons for poor quality as indicated by them were: limited availability of ice (75%), lack of infrastructure facilities (65%), uncertainty of markets (52%), lack of emphasis on quality (47%) and poor access to available technologies (41%). Respondents to the questionnaire also identified: unavailability of potable water, insulated boxes, good landing jetty, racks for drying fish, poor cold storage facilities and limitations in dried fish storage facilities, as further factors leading to the loss of quality in their products. Results demonstrate that improvements to the infrastructure facilities and conducting of proper awareness programmes on handling practices could lead for improvements in the quality of value added products prepared from the shrimp fishery by-catch at Kalpitiya.

The effect of artisanal preservation methods on nutritional security of “Mukene” Rastrineobola argentea caught from Lakes Victoria and Kyoga in Uganda

The artisanal fish preservation methods in Uganda are characterized by extreme operating conditions. Consequently, vital nutritional components diminish in value and quantity which renders fish consumer nutritionally insecure. To establish the magnitude of nutritional loss, duplicate samples of Mukene Rastrineobola argentea were collected from Kiyindi landing site on L. Victoria and Moone landing site on L. Kyoga. Each set of duplicate samples was divided into five portions and kept on ice. For each preservation method a portion was processed into respective products at Food Bioscience and Agri-Business Laboratories aside from the control (fresh) sample. Both preserved and control samples were analysed for nutrient loss at Department of Chemistry, Makerere University using AOAC methods. The composition of fatty acids was determined by methanolysis gas chromatography and Mass spectrophotometry of the resultant methyl esters. The results indicate that nutrients of all preserved samples did not vary significantly from the control except for some fatty acids. The Eicosapentaenoic acid (EPA) in fresh samples declined from 6.72% to 1.08% in deep-fried samples constituting 83.93% nutrient loss. The sum ratio w3:w6 as well as EPA: DHA (Docosahexaenoic) ratio in fried samples also varied significantly (p<0.5) lower than 0.668 and 0.20 for the average of either preservation methods and experts recommended ratio respectively. Further research has been recommended to ascertain the causative factor, since Mukene frying is being promoted in the Great lakes region as alternative method to sun-drying. In conclusion, regular consumers of fried Mukene do not benefit much from the nutritional and health attributes of Omega 3 and 6.

La peche dans le fleuve Niger

The fish production of the River Niger can best be estimated from a country by country evaluation of the tonnage exported and that consumed locally. All exported and some locally consumed fish are preserved by smoking or sun drying, a process which entails a loss of weight. Coefficients to correct for this of between 2.6 to 4 have been calculated depending on the type of product. A further loss occurs due to handling and to insect attack, which may account for up to 40% of the production. Taking the above factors into account the productions estimated for the various countries of the Niger River basin are as follows: Guinea (3,600 t), Mali (90,000 t), Upper Volta and Ivory Coast (negligible), Niger (5,200 t), Dahomey (1,200 t), Nigeria (25,000 t), Cameroon (3,000 t). A total production of 128,000 t is, therefore, obtained for the basin as a whole, excluding the Kainji Reservoir. At this level of production, there have been no intimations of overfishing from any part of the basin, and there is unanimity that fishing could be intensified. On the basis of the estimates of existing production and local estimates of potential production it is possible that up to 200,000 t of fish could be produced annually from the basin as a whole.