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close this bookBioconversion of Organic Residues for Rural Communities (UNU, 1979)
View the documentFrom the charter of the United Nations University
View the documentForeword
close this folderPerspectives on bioconversion of organic residues for rural communities
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View the documentIntroduction
View the documentSources of available nutrients
View the documentThe most suitable materials for bioconversion
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View the documentMicrobial conversion
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close this folderAvailability of organic residues as a rural resource
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View the documentDiscussion summary: Papers by van der Wal and Barreveld
close this folderMicro-organisms as tools for rural processing of organic residues
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View the documentMicrobial utilization of mono- and di-saccharide residues
View the documentMicrobial conversion of starchy residues
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View the documentMicrobial utilization of cellulose and ligno-cellulose residues
View the documentAlgal culture as a source of biomass
View the documentMicrobial utilization of silviculture biomass
View the documentMicro-organisms and marine and freshwater biomass
View the documentInternational studies on processing organic residues
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close this folderProduction of feed as an objective for bioconversion systems
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close this folderEnvironmental goals for microbial bioconversion in rural communities
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View the documentHealth and water economy
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View the documentDiscussion summary: Papers by Porter, Berk and La Rivière
close this folderStrategies for developing small-scale fermentation processes in developing countries
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close this folderProduction of microbial protein foods on edible substrates, food by-products, and ligno-cellulosic wastes
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View the documentContributions to the solution of nutritional problems
View the documentDevelopment of protein-rich vegetarian meat substitutes in the western world
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close this folderThe role of ruminants in the bioconversion of tropical byproducts and wastes into food and fuel
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View the documentNutritional limitations in the use of tropical by-products and waste
View the documentPractical experience with tropical by-products and wastes as feed for ruminants
View the documentAn integrated system for converting tropical feeds and byproducts into milk, beef, and fuel
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close this folderPossible applications of enzyme technology in rural areas
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View the documentBiocatalytic processes
View the documentEnzyme hydrolysis of manioc
View the documentWhole cell systems
View the documentCellulose degradation and utilization
View the documentTransfer of enzyme technology to rural communities
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close this folderIndian experience with treated straw as feed
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View the documentExperience with straw treatment
View the documentField testing and demonstration of straw treatment
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View the documentAnnex 1. The energy efficiency of the two-stage, feed-fuel processing of straw in indian villages
View the documentAnnex 2. Method of calculating the value presented in table 2 for the efficiency of naoh energy usage
View the documentAnnex 3. Recommendations to farmers on the treatment of straw
View the documentAnnex 4. Calculated efficiency of milk production by straw-fed village buffaloes
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close this folderIndian experience with algal ponds
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View the documentCultivation of algae in wastes for feed
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close this folderOrganic residues in aquaculture
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View the documentThe range of production in aquaculture
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close this folderBiogas generation: developments. Problems, and tasks - an overview
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View the documentWhat is biogas?
View the documentMicrobiology of CH4, or bio-methanogenesis
View the documentThe biogas plant-some technical considerations
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close this folderMushroom production technology for rural development
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View the documentGrowing mushrooms under semicontrolled conditions
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close this folderThe combination of algal and anaerobic waste treatment in a bioregenerative farm system
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close this folderA continuous composting system for disposal and utilization of animal wastes at the village level
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View the documentA continuous composting system for land utilization of animal wastes at the village level
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close this folderBioconversion of fruit and vegetable wastes
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close this folderIntegrated research on agricultural waste reclamation
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View the documentProduction of yeast from soybean cooking waste at miso factories
View the documentApplication of soy waste as koji substrate for rice miso manufacturing (5, 6)
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close this folderSolid state fermentation of starchy substrates
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close this folderProduction of single-cell protein from cellulose
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close this folderAnalysis of energy cost of integrated systems
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close this folderAnalysis of bioconversion systems at the village level
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View the documentSome results and costs from integrated systems
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close this folderNutritional evaluation of bioconversion products for farm animals
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close this folderBioconversion products: toxicology - problems and potential
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close this folderNutritional evaluation in humans
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View the documentEvaluation of products of bioconversion for human consumption
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View the documentThe evaluation of various food products
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View the documentDiscussion summary: Papers by van Weerden, Shacklady, and Bressani
close this folderBiomass from organic residues for animal and human feeding
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close this folderAppropriate biotechnology - summary remarks
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close this folderOther UNU Publications
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Introduction

Straw is a major by-product of crop production in the world. It is potentially useful as a source of energy, though it also contains worthwhile amounts of plant nutrients. Being bulky, it must, for the most part, be processed on the farm where it is produced. Ploughing it under or composting it are efficient wads of recycling plant nutrients, but these methods waste all of the energy the straw contains. In India virtually all straw is put through a two-stage process that both taps some of its energy and recycles plant nutrients. This process consists of feeding the straw to livestock and then using the dung as fuel. Usually, the dung is dried and burned directly, but this is undesirable because nitrogen is lost. A significant improvement is the introduction of the biogas plant to produce fuel gas from the dung; nitrogen is recovered from the slurry after fermentation (1 - 3). The efficiency of this two-stage, feed-fuel system ranges from 9 to 14 per cent (Annex 1).

Aside from purely energy considerations, the Indian system of processing straw on the farm has much to commend it. The relative simplicity of using an animal to convert straw energy to draught power is perhaps foremost. The same applies to milk production, a process in which straw provides the energy for the bioconversion of low-quality, inedible plant proteins (miscellaneous vegetation, grain-and oilseed-milling offals) into high-quality milk protein; the gain is not simply in proportion to the energy converted. Finally, it may be noted that straw cannot be used as a fuel in villages unless it is first passed through an animal; even present-day biogas plants cannot handle straw directly.

The efficiency of the livestock feed step can be increased by treating the straw before it is fed. The data presented in this paper indicate that the live weight gain in growing animals can be increased substantially if the straw is treated. The overall energy recovery from straw might not increase as a result of straw treatment because the more complete digestion of the treated straw by the animal would leave relatively less dung for use as fuel. Milk is, however, a more valuable form of energy than fuel.

The purpose of this paper is to review the Indian experience with various methods of straw treatment. It will include a discussion of the improvements obtained in animal productivity, the economics of such treatment, as well as the larger considerations of its energy cost and environmental impact. A special point made in this paper is that straw treatment techniques, like any new farming practice, will have to be evaluated on small private farms; satisfactory testing in an experiment station is not possible. A procedure for farm testing is outlined.