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Workshop in the state of the art of bioconversion of organic residues for rural communities

This workshop, jointly sponsored by the United Nations University programmes on world hunger and natural resources, was held in Guatemala, 13 - 15 November 1978, with the Institute of Nutrition of Central America and Panama, and the Tropical Agricultural Research and Training Centre, Turrialba, Costa Rica, as the local hosts. The proceedings will be published by the United Nations University during 1979.

The workshop began with a review of the perspectives for bioconversion of organic residues for rural communities, availability of organic residues as a rural resource, and micro-organisms as tools for rural processing of organic residues. Other topics on the first day were production of feed as an objective for bioconversion system; environmental goals of microbial bioconversion in rural communities; lessons from experience in small-scale fermented food production, and possible application of enzyme technology in rural areas.

On the second day, case studies of experiences with bioconversion of organic residues into feed were presented. These included experience with processed straw as feed; algal ponds; the utilization of biomass in Asian fish ponds; biogas production; mushroom cultivation on straw; the production and use of algae from sewage; bioconversion of organic residues into feed; utilization of animal wastes, and of fruit and vegetable wastes. Projects of integrated research on agricultural waste reclamation, solid fermentation of starch substrates, and utilization of cellulosic residues were also described.

The morning of the third day was devoted to the nutritional and toxicological evaluation of microbial biomass and related public health concerns. Attention then turned in the afternoon to analysis of the cost of integrated systems and of the costs and benefits of alternative approaches, and of the feasibility of bioconversion systems at the village level.

The extensive discussions following each presentation will be summarized, and included in the publication of the proceedings.


A contribution from the UNU workshop held in November 1978 in Guatemala on "The State of the Art of Bioconversion of Organic Residues for Rural Communities" that merits immediate attention is the decision to apply a separate name and acronym to distinguish microbial biomass product (MBP) from single-cell protein (SCP). The term SCP has been applied to describe the biomass produced on relatively pure substrates, and consisting entirely of the cells of a single organism or a limited number of species. The designation met a need and came rapidly into world-wide use.

It is now proposed that the term "microbial biomass product", or MBP, be applied to the complex mixture of substrate and micro-organisms produced by the fermentation of unrefined animal and vegetable wastes. It is obviously intended to complement the term SCP, and to avoid the extension of its use to the complex combinations of substrate and micro-organism that were the main concern of the workshop.

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