Biorefineries – creating economic opportunities from biofuels and bio-products

Biorefineries, producing fuels, green chemicals and bio-products, offer great potential for improving the profitability and sustainability of tropical agricultural industries. Biomass from tropical crops like sugarcane, sweet sorghum, palm and cassava offer great potential because of the high biomass growth potential under favourable climatic conditions. Biorefineries aim to convert waste residues through biochemical and enzymatic processes to low cost fermentable sugars which are a platform for value-adding. Through subsequent fermentation utilising microbial biotechnologies or chemical synthesis, the sugars can be converted to fuels including ethanol and butanol, oils, organic acids such as lactic and levulinic acid and polymer precursors. Other biorefinery products can include food and animal feeds, plastics, fibre products and resins. Pretreatment technologies are a key to unlocking this potential and new technologies are emerging. This paper will address the opportunities available for tropical biorefineries to contribute to the future profitability of tropical agricultural industries. The importance of pretreatment technologies will be discussed.

Utilisation of local ingredients in commercial pig feeds

The long-term competitiveness of the both the Vietnamese feed and pig production industries are constrained and under pressure whilst the industry is dependent on the use of imported feed ingredients in diets for animal production. These cost pressures are a result of import taxes, transport costs, currency fluctuations and feed supply limitations. By undertaking studies on available resources which are currently under-utilised and with potential as local feeds, we can prove their suitability for use as feedstuffs in pig diets and as replacements for imported feed ingredients. In undertaking this process we can lower feeding costs for pig production in Vietnam by the use of local feeds which are cheaper, generate new industries in Vietnam harvesting or processing these feeds and increase the incomes of Vietnamese workers who are involved in producing these by-products. Our project has shown that rubber seed, when processed correctly to lower the hydrogen cyanide content, is a safe and suitable protein meal feedstuff for use in pig diets with the potential to replace significant quantities of imported soybean and fishmeal in Vietnamese pig diets as long as diets are balanced for any amino acid shortfalls. Our peanut studies have shown that use of binders can help alleviate pig production problems with aflatoxin content in peanut meals. Further work is needed to characterise the fate of the bound aflatoxin to see if there is any meat residue risk. Cassava residue is a resultant by-product from starch extraction in both large and small cassava processing factories. Sub-samples from these two mill types were collected and evaluated for residue HCN. Analyses has shown that the processing and sun drying results in a product with relatively consistent low HCN content. Chemical analyses also reveal that significant residual starch also remains in this by-product. Digestibility studies and pig performance feeding studies have shown that cassava residue can be included in diets at 30% with no adverse effect, although the higher fibre content of this product means that strategically, cassava residue is more suitably used in finisher and sow diets. Research has examined the digestible energy content of a number of sunflower meal types available in Australia and identified major differences in their energy value based on processing, additionally, amino acid analysis has shown a significantly lower lysine content than previous reported. We also examined the digestible energy content of a number of Australian stylo forage legume harvest batches and identified the differences in their energy value based on age/harvest time of the forage legume. Analysis results of various stylo cuts showed that the early cut stylo has a higher starch content and lower fibre fraction content than observed in late and recut stylo which were allowed to grow longer. As a result the faecal digestible energy content was higher for the early cut stylo than for the subsequent cut stylo material which had been allowed to become woody. The results have shown that feeding of stylo meal does provide some nutritive value to the pig with increased energy and nitrogen supply, with a portion of the nitrogen presented which the pig is able to retain. Based on nutrient and fibre content stylo could have a useful role in sow feeding and satiety under non-stall housing situations. With increasing Vietnamese investment in rubber production seen with larger areas under plantations the amounts of rubber seed available for animal feeding will grow significantly over the next 15 years and the importance of the by-product ie rubber seed meal as a protein source in diets for Vietnamese pigs.

Effectiveness of Various Artificial Larval Diets for Rearing Bactrocera passiflorae (Froggatt) and B. xanthodes (Broun) in the Laboratory in Fiji

Laboratory colonies of Bactrocera passiflorae (Froggatt) and B. xanthodes (Broun) were established at Koronivia Research Station, Fiji in 1991. Laboratory rearing of the two economically important species was a prerequisite to studies conducted on protein bait spray and quarantine treatment development. To increase the production of laboratory reared fruit flies for this research and also to have a substitute larval diet available, replicated comparisons of the effectiveness of larval diets were carried out using B. passiflorae and B. xanthodes. The diets compared were pawpaw/bagasse, dehydrated carrot and diets used for culturing Mediterranean fruit fly (Ceratitis capitata Wiedemann), Oriental fruit fly (B. dorsalis Hendel), melon fly (B. cucurbitae Coquillett) and B. latifrons (Hendel), pawpaw diet and breadfruit diet. B. passiflorae and B. xanthodes eggs seeded onto the various diets were allowed to develop into larvae, pupae and adults. The percentage egg hatch, number of pupae recovered, percentage pupal mortality, weight of 100 pupae, number of adults and percentage eclosion were used to determine the effectiveness of the diets. Results showed that pawpaw/bagasse and dehydrated carrot diets performed favorably for both species. The pawpaw diet currently used as standard larval diets for both species is the most readily available and easiest to use. Breadfruit diet was tested on B. xanthodes only and showed that it was a suitable substitute for the pawpaw-based diets. Other larval diets, cassava/pawpaw and banana diets, that have been developed and used in the South Pacific areas are also discussed in this paper. When pawpaw or breadfruit are not available, dehydrated carrot diet may be substituted for fruit-based larval diets.

The Significance of Wild Plants in the Evolutionary Ecology of Three Major Viruses Infecting Cultivated Sweetpotato in Uganda

The studies presented in this thesis contribute to the understanding of evolutionary ecology of three major viruses threatening cultivated sweetpotato (Ipomoea batatas Lam) in East Africa: Sweet potato feathery mottle virus (SPFMV; genus Potyvirus; Potyviridae), Sweet potato chlorotic stunt virus (SPCSV; genus Crinivirus; Closteroviridae) and Sweet potato mild mottle virus (SPMMV; genus Ipomovirus; Potyviridae). The viruses were serologically detected and the positive results confirmed by RT-PCR and sequencing. SPFMV was detected in 24 wild plant species of family Convolvulacea (genera Ipomoea, Lepistemon and Hewittia), of which 19 species were new natural hosts for SPFMV. SPMMV and SPCSV were detected in wild plants belonging to 21 and 12 species (genera Ipomoea, Lepistemon and Hewittia), respectively, all of which were previously unknown to be natural hosts of these viruses. SPFMV was the most abundant virus being detected in 17% of the plants, while SPMMV and SPCSV were detected in 9.8% and 5.4% of the assessed plants, respectively. Wild plants in Uganda were infected with the East African (EA), common (C), and the ordinary (O) strains, or co-infected with the EA and the C strain of SPFMV. The viruses and virus-like diseases were more frequent in the eastern agro-ecological zone than the western and central zones, which contrasted with known incidences of these viruses in sweetpotato crops, except for northern zone where incidences were lowest in wild plants as in sweetpotato. The NIb/CP junction in SPMMV was determined experimentally which facilitated CP-based phylogenetic and evolutionary analyses of SPMMV. Isolates of all the three viruses from wild plants were genetically similar to those found in cultivated sweetpotatoes in East Africa. There was no evidence of host-driven population genetic structures suggesting frequent transmission of these viruses between their wild and cultivated hosts. The p22 RNA silencing suppressor-encoding sequence was absent in a few SPCSV isolates, but regardless of this, SPCSV isolates incited sweet potato virus disease (SPVD) in sweetpotato plants co-infected with SPFMV, indicating that p22 is redundant for synergism between SCSV and SPFMV. Molecular evolutionary analysis revealed that isolates of strain EA of SPFMV that is largely restricted geographically in East Africa experience frequent recombination in comparison to isolates of strain C that is globally distributed. Moreover, non-homologous recombination events between strains EA and C were rare, despite frequent co-infections of these strains in wild plants, suggesting purifying selection against non-homologous recombinants between these strains or that such recombinants are mostly not infectious. Recombination was detected also in the 5 - and 3 -proximal regions of the SPMMV genome providing the first evidence of recombination in genus Ipomovirus, but no recombination events were detected in the characterized genomic regions of SPCSV. Strong purifying selection was implicated on evolution of majority of amino acids of the proteins encoded by the analyzed genomic regions of SPFMV, SPMMV and SPCSV. However, positive selection was predicted on 17 amino acids distributed over the whole the coat protein (CP) in the globally distributed strain C, as compared to only 4 amino acids in the multifunctional CP N-terminus (CP-NT) of strain EA largely restricted geographically to East Africa. A few amino acid sites in the N-terminus of SPMMV P1, the p7 protein and RNA silencing suppressor proteins p22 and RNase3 of SPCSV were also submitted to positive selection. Positively selected amino acids may constitute ligand-binding domains that determine interactions with plant host and/or insect vector factors. The P1 proteinase of SPMMV (genus Ipomovirus) seems to respond to needs of adaptation, which was not observed with the helper component proteinase (HC-Pro) of SPMMV, although the HC-Pro is responsible for many important molecular interactions in genus Potyvirus. Because the centre of origin of cultivated sweetpotato is in the Americas from where the crop was dispersed to other continents in recent history (except for the Australasia and South Pacific region), it would be expected that identical viruses and their strains occur worldwide, presuming virus dispersal with the host. Apparently, this seems not to be the case with SPMMV, the strain EA of SPFMV and the strain EA of SPCSV that are largely geographically confined in East Africa where they are predominant and occur both in natural and agro-ecosystems. The geographical distribution of plant viruses is constrained more by virus-vector relations than by virus-host interactions, which in accordance of the wide range of natural host species and the geographical confinement to East Africa suggest that these viruses existed in East African wild plants before the introduction of sweetpotato. Subsequently, these studies provide compelling evidence that East Africa constitutes a cradle of SPFMV strain EA, SPCSV strain EA, and SPMMV. Therefore, sweet potato virus disease (SPVD) in East Africa may be one of the examples of damaging virus diseases resulting from exchange of viruses between introduced crops and indigenous wild plant species. Keywords: Convolvulaceae, East Africa, epidemiology, evolution, genetic variability, Ipomoea, recombination, SPCSV, SPFMV, SPMMV, selection pressure, sweetpotato, wild plant species Author s Address: Arthur K. Tugume, Department of Agricultural Sciences, Faculty of Agriculture and Forestry, University of Helsinki, Latokartanonkaari 7, P.O Box 27, FIN-00014, Helsinki, Finland. Email: tugume.arthur@helsinki.fi Author s Present Address: Arthur K. Tugume, Department of Botany, Faculty of Science, Makerere University, P.O. Box 7062, Kampala, Uganda. Email: aktugume@botany.mak.ac.ug, tugumeka@yahoo.com

Developments and Microbiological applications in African foods: Emphasis on Nigerian Wara cheese

African indigenous foods have received limited research. Most of these indigenous foods are fermented and they form part of the rich nutritional culture of many groups in African countries. The industrialization and commercialisation of these indigenous African fermented foods should be preceded by a thorough scientific knowledge of their processing which can be vital in the elimination of hunger and poverty. This study highlighted emerging developments and the microbiology of cereal-based and cassava-based food products that constitute a major part of the human diet in most African countries. In addition, investigations were also carried out on the coagulant of the Calotropis procera plant used in traditional production of Nigerian Wara cheese and on the effects of adding a nisin producing Lactococcus lactis strain originating from human milk to Nigerian Wara cheese. Fermented cereal-based food such as ogi utilize popular African and readily available grains maize, millet or sorghum as substrates and is popular as a weaning diet in infants. In this study, the bulkiness caused by starch gelatinization was solved by amylase treatments in the investigation on cooked and fermented oat bran porridge. A similar treatment could reduce the viscosity of any cereal porridge. The properties of the Sodom apple leaves (Calotropis procera) extract in cheesemaking were studied. C. procera was affected by monovalent (K+ and Na+) and divalent (Mg2+ and Ca2+) cations during coagulation. The rennet strength of this coagulant was found to be 7 % compared to animal rennet at 35 °C. Increasing the incubation temperature to 70 °C increased the rennet strength 28-fold. The molecular weight of the partially purified protease was determined by SDS-PAGE and was confirmed by Zymography to be approximately 60 kilodaltons. The high proteolytic activity at 70 °C supported the suitability of the protease enzyme as a coagulant in future commercial production of Nigerian Wara cheese. It was also possible to extend the shelf life of Wara cheese by a nisin producing lactic acid bacteria Lactococcus lactis LAC309. The levels of nisin in both whey and curd fractions of Wara were investigated, results showed a 3 log reduction of toxicogenic Bacillus licheniformis spiked on Wara after 3 days. These studies are the first in Finland to promote the advancement of scientific knowledge in African foods. Recognizing these indigenous food products and an efficient transfer of technology from the developed countries to industrialize them are necessary towards a successful realization of the United Nations Millenium Development Program.

Ruokauskomukset Mosambikin maaseudun raskaana olevilla ja imettävillä naisilla

Ihmisille ympäri maailmaa on tyypillistä valita tiettyjä ruokia suuremmasta valikoimasta syömäkelpoista ruokaa ja luoda mieltymyksiä sekä kieltoja joitakin ruokia kohtaan. Näitä ilmiöitä kutsutaan ruokauskomuksiksi ja ne ovat tärkeä osa kulttuuria. Niiden taustalla on usein terveydelliset perustelut tai sosiaalinen arvostus yhteisössä. Afrikassa on todettu olevan paljon erilaisia ruokauskomuksia, jotka kohdistuvat usein raskaana oleviin ja imettäviin naisiin sekä lapsiin, ryhmään, joka on fysiologisesti erityisen herkässä elämänvaiheessa. Ravitsemustilan tai ruokaturvan ollessa heikko, mahdollisilla ruokauskomuksilla voi olla merkittävät seuraukset erityisesti tämän väestönosan terveydentilaan. Aliravitsemus ja virheravitsemus ovat edelleen suuria ongelmia Afrikassa ja muissa kehittyvissä maissa. Tämän työn tavoitteena oli tutkia laadullisin menetelmin, onko erityisesti raskaana olevilla ja imettävillä naisilla Keski-Mosambikin maaseudulla, Zambézian maakunnassa, ruokauskomuksia, mitä ne mahdollisesti ovat, sekä arvioida voiko ruokauskomuksilla olla ravitsemuksellista merkitystä. Menetelminä oli 5 ryhmähaastattelua kolmessa kylässä ja 10 yksilöhaastattelua kahdessa kylässä. Tutkittavat olivat 12–78-vuotiaita naisia ja heitä oli yhteensä 27. Tulkkaus, tutkimusaiheen sensitiivisyys ja haastattelijan kokemattomuus aiheuttivat haasteita haastatteluiden toteutukseen. Tämän vuoksi menetelmää muokattiin ja se vaihdettiin ryhmähaastattelusta yksilöhaastatteluun tutkimuksen aikana. Ruokauskomukset vaihtelivat sekä kylien välillä että kylien sisällä, joskin niistä löytyi samantyyppisiä pääpiirteitä. Työssä todettiin, että raskaana oleviin ja imettäviin naisiin kohdistui tutkimusalueella ruokauskomuksia. Raskauden aikana tuli välttää pääasiassa proteiinipitoisia ruokia, kuten lihaa ja kalaa ja puolestaan suosia kasvisten, hedelmien ja viljatuotteiden käyttöä. Linnun munien syöntiä sekä suositeltiin että kehotettiin välttämään raskauden aikana. Raskauden aikana ilmeni lisäksi tietoinen tapa vähentää kassavapuuron tai ruuan syömistä kokonaisuudessaan. Imetyksen aikana ei vältetty juuri mitään ruokia, vaan suositeltiin kookosta ja kasviksia. Suurin osa perusteluista liittyi äidin ja lapsen terveyteen. Perustelut voitiin jakaa seuraaviin ryhmiin: lisää äidinmaidon tuotantoa; aiheuttaa vatsakipua äidillä; pitää yllä kuntoa ja estää vatsan kasvua; äidistä tulee vahva, terve ja hän saa vitamiineja; lapsen ulkonäkö muuttuu; lapsesta tulee terve ja vahva; lapsen käyttäytyminen muuttuu; aiheuttaa keskenmenon; aiheuttaa vaikean tai helpon synnytyksen. Ruokauskomukset ja terveysviranomaisilta tullut valistus oli osittain sekoittunut keskenään. Lähes kaikki naiset kertoivat noudattavansa näitä ruokauskomuksia. Muutamat naiset kertoivat suositeltavien ruokien kohdalla, että ruokien saatavuus tekee noudattamisen joskus vaikeaksi. Proteiinipitoisten ruokien välttäminen voi lisätä proteiinialiravitsemuksen riskiä ja syömisen vähentäminen saattaa lisätä riskiä saada riittämättömästi energiaa raskauden aikana. Suositeltavat ruuat todennäköisesti edistävät terveyttä. Tutkielman perusteella voitiin todeta, että vieraassa kulttuurissa tutkiminen vaatii tutkimusmenetelmältä paljon. Tärkeää on menetelmän joustavuus, jotta sitä voi muuttaa tutkimuskentällä toimivampaan ja luotettavampaan muotoon. Johtopäätöksenä todettiin, että suositeltavin menetelmä tutkittaessa ruokauskomuksia tällä tutkimusalueella olisi ollut yksilöhaastattelut, jossa olisi ollut mahdollisimman vähän osallistujia ja osallistujat olisivat olleet samaa sukupuolta ja saman ikäisiä. Terveyden ja ravitsemuksen kannalta on tärkeää, että ruokauskomuksista ollaan tietoisia ja väestön ruokauskomuksia tutkitaan alueittain, koska ne voivat vaihdella merkittävästi jopa kylien tai ihmisryhmien sisällä.

Jatrophanviljely ja maankäyttö Vietnamissa

Biofuels are under discussion all over the world today. There are fears that the farming of biofuel plants hurts food production and weakens the food security of the poor. On the other hand, biofuel production could lessen the green house gas emissions caused by transportation, and it could also spread the profits from fuel markets more evenly between countries. The aim of this thesis is to find out how an oil plant called jatropha curcas L., which is used for biodiesel production, can affect the sustainability of livelihoods in Vietnam from the point of view of land use. Special attention is given to the effects of jatropha farming on food production, land productivity, natural resources of livelihoods and global livelihood. Jatropha belongs to the family Euphorbiaceae, and it grows naturally in tropical and subtropical areas. It can be grown on poor soils, its seeds have high oil content, and it cannot be eaten due to its toxicity. The plant grows naturally in Vietnam, and during the past few years it has also begun to be farmed for making biodiesel. Population growth in Vietnam has slowed down, but the population's standard of living and energy consumption are still rising quickly. An interest in the international biodiesel markets has awoken following Vietnam's opening up to international trade. Jatropha diesel plays a significant part in Vietnam’s clean fuel strategy, and many companies have set up jatropha plantations to produce raw material for biodiesel. Diesel made from jatropha is planned to be used both locally and for export. This thesis uses a theoretical concept of sustainable livelihoods. According to the theory, the resources that people have shape their livelihood possibilities. Farming of jatropha affects the livelihoods of people especially through land use, as land use changes have effects on many of the livelihood resources. In addition to the written sources, the material of the thesis is based on 14 interviews in Vietnam and Finland, and on observation during a field trip to Northern Vietnam in the spring of 2008. The results of the thesis show that jatropha diesel can support the sustainability of livelihoods at different scales if it is produced with deliberation. However, positive results are only possible if decisions are made carefully and more experience is collected. The possibilities of sustainable jatropha farming depend mainly on the previous land use methods and ways of production. Farming of jatropha does not threaten food production in Vietnam if the farming plans are implemented as planned. Jatropha may take some land from cassava, but at the same time, food production can be increased if mixed farming is used on some farms. Plenty of new research information and practical experiences on jatropha farming has to be collected before results of the real sustainability of the farming are ready. Carefully considered continuation and documentation of present and future projects would help to understand the possibilities of jatropha diesel in Vietnam and elsewhere.

An Efficient Probe for Rapid Detection of Cyanide in Water at Parts per Billion Levels and Naked-Eye Detection of Endogenous Cyanide

A new molecular probe based on an oxidized bis-indolyl skeleton has been developed for rapid and sensitive visual detection of cyanide ions in water and also for the detection of endogenously bound cyanide. The probe allows the naked-eye detection of cyanide ions in water with a visual color change from red to yellow ((max)=80nm) with the immediate addition of the probe. It shows high selectivity towards the cyanide ion without any interference from other anions. The detection of cyanide by the probe is ratiometric, thus making the detection quantitative. A Michael-type addition reaction of the probe with the cyanide ion takes place during this chemodosimetric process. In water, the detection limit was found to be at the parts per million level, which improved drastically when a neutral micellar medium was employed, and it showed a parts-per-billion-level detection, which is even 25-fold lower than the permitted limits of cyanide in water. The probe could also efficiently detect the endogenously bound cyanide in cassava (a staple food) with a clear visual color change without requiring any sample pretreatment and/or any special reaction conditions such as pH or temperature. Thus the probe could serve as a practical naked-eye probe for in-field experiments without requiring any sophisticated instruments.

The use of locally available materials in fish feed production

In Nigeria, the culture of fish is gaining importance, but local fish farmers face a set back because of the stoppage on importation of fish feed. Locally available raw materials such as yam, plantain, banana, cowpeas, macuna, maize, cassava, millet, sorghum, groundnut, sunnhemp seed and brewery wastes are considered as potential materials for fish feed. These have been examined on their minimum protein contributions since this is the most expensive part of the fish feed. Alternative sources to animal proteins are also examined. Plant protein from groundnut, melon, mucuna and others compare favourably with bloodmeal mixture and thus can be used to replace the more expensive animal proteins. Pellet feed can be produced on a small scale or commercial basis from the locally available raw materials and the fish farmer is advised to seek assistance from qualified fisheries personnel

Nutrient digestibility and growth response of rainbow trout (Salmo gairdneri ) fed different carbohydrate types

Seven groups of fingerling rainbow trout (S. gairdneri ) were fed for 10 weeks on 0%, 10%, 20% and 30% of cassava or rice in isonitrogenous diets. Optimum growth and food utilization was at 20% dietary cassava. High fiber content of the control diet did not suppress protein digestibility in this group. Rather, at all levels, protein digestibility was good and remained between 84.4% and 90.1%. However, in the control group, carbohydrate digestibility was very poor. The cassava diets which had the highest digestible energy as carbohydrate produced the best growth performance, food utilization and protein sparing. At the levels studied, the dietary carbohydrates produced no hyperglycamic effect on the fish

Preliminary investigation into implication of a single cell organism in fish feed bouyancy and flotation

Two Isocaloric Isoproteic 30% crude protein diets were formulated for Clariid catfish and Tilapia with wheat grain starch (WGS) and cassava tuber starch (CTS) incorporated at 10 percent as binding agents. Saccharomyces cerevisiae was included at 2% as floating additive. The water stability, nutrient retention and flotation of pelleted feeds were observed for 60 minutes. There were generally decreasing trends in stability and retention at increasing time of immersion in water. The lipid retention was higher (P>0.05) than proteins in both diets. WGS diet was better (P>0.05) than CTS diet in flotation, which has attributed to the presence of gluten protein in wheat products. It is envisaged that a break through in floating feed development in Nigeria aquaculture would save the Nigeria economy from extruded (floating) feed importation

Étude préliminaire sur l'incorporation de liants dans un aliment composé pour poisson d'élevage en Côte d'Ivoire

Artificial feeding constitutes a very important aspect for intensive fish culture. Then, the physical properties, particularly water stability of feed, wider influence the fish production. By trying to find some answers to these problems, a preliminary study on water stability has been conducted at the LAYO aquaculture research station. This work consisted in incorporating different types of binders available in tropical countries in fish pellets of 3.5 mm and 6.0 mm diameters in order to identify an efficient binder allowing the improvement of the water stability of feed. From this experiment, it comes out that the use of wheat flour (A1) gives excellent quality pellets followed by cassava flour residue (A3). Moreover, this study shows that it exists an influence of the diameter on the crumbling of the pellets.

Fermentação alcoólica de hidrolisado de farelo de mandioca usando levedura Saccharomyces cerevisiae álcool resistente

A matriz energética mundial é baseada em fontes fósseis e renováveis. No Brasil, o bioetanol é gerado principalmente a partir da cana-de-açúcar. Resíduos agroindustriais (fontes celulósicas ou amiláceas) despontam como biomassas alternativas à cana-de-açúcar, para aumentar a competitividade deste combustível renovável frente aos de origem fóssil e também favorecer a sustentabilidade e a segurança alimentar e energética, pois são ricos em polissacarídeos não diretamente fermentescíveis, abundantes (problema ambiental) e apresentam baixo valor comercial. O farelo de mandioca é um exemplo de resíduo sólido gerado na produção de fécula (amido) e farinha de mandioca que ainda contém, em média, 75% de amido. Consequentemente, deve ser previamente hidrolisado e posteriormente fermentado por leveduras do gênero Saccharomyces para gerar etanol. O objetivo deste estudo foi produzir bioetanol a partir de hidrolisados enzimáticos de farelo de mandioca, usando levedura álcool resistente (AR). Primeiramente, a concentração de açúcares obtida a partir da hidrólise enzimática foi verificada através de um planejamento fatorial completo (24), com triplicata no ponto central, a fim de investigar a influência dos seguintes fatores na hidrólise: concentração de α-amilase (Termamyl 2X), tempo de liquefação, concentração de glucoamilase (AMG 300L) e o tempo sacarificação. A condição de hidrólise mais favorável foi a do ensaio com 0,517 mL de AMG/g amido, 0,270 mL de Termamyl/g amido, 1h de tempo de liquefação e 2h de tempo de sacarificação. O caldo resultante da condição escolhida alcançou altas concentrações de glicose (160 g/L). Os ensaios de fermentação alcoólica foram realizados em duplicata em biorreator de 3L, em regime de batelada, a 30C, 100 rpm e pH 5,5. Cerca de 3 g/L (massa seca) de uma linhagem de levedura álcool tolerante, Saccharomyces cerevisiae Hansen BY4741, crescida por 12h em meio YEDP (2% de glicose) foram usados como inóculo. O mosto consistiu de um litro de hidrolisado (160 g/L de glicose) fortificado com extrato de levedura (1%) e peptona de carne (1%), além da adição de um antiespumante (Tween 80) na concentração de 0,05% (m/v). Em 30 horas de fermentação, a média da concentração de etanol obtida foi de 65 g/L. A eficiência foi de 87,6% e o rendimento e a produtividade foram 0,448 e 2,16 g/L.h, respectivamente. Os resultados indicaram a aplicabilidade do farelo de mandioca como matéria-prima para a produção de bioetanol

Integrated farming: a new approach in the Basse Casamance, Senegal

Environmental changes due to 2 decades of drought have modified the ecosystem of the Basse Casamance, Senegal thus forcing farmers to change their practices. They have built fish ponds and diversified into crops such as peanut, millet, sorghum, cassava and vegetables. The ponds have 2 purposes - to protect ricefields against inflow of brackishwater and to raise fish. The fish complements rice, which is the main diet, adding animal protein and serving as a source of income. Although this integrated farming system is little developed at present, it has good potential to rationalize use of the resources available to farmers and to promote interactions between farm enterprises.

Survival and changes in the fine structure of selected tissues of Penaeus monodon Fabricius juveniles fed various carbohydrates

Penaeus monodon juveniles were reared on semipurified diets containing various carbohydrates (maltose, sucrose, dextrin, molasses, cassava starch, corn starch or sago palm starch). Significant differences were observed between the type as well as the level of carbohydrate in the diet on the survival of the juveniles. Results indicate that there does not seem to be any correlation between survival and the complexity of the carbohydrates.