Development of designer microbial consortia for bioconversion of cellulose to energy and value-added products

随着传统能源供应的减少，人们越来越需要可持续地生产有用的可再生能源。将丰富的能源--植物生物质--生物转化为有机燃料、氢气、电力和其他有用的产品，是化石燃料的一个可行的替代品。纤维素是植物生物量和纤维素废弃物的主要成分，可被多种降解纤维素的好氧细菌和厌氧细菌以及混合培养物分解。微生物降解纤维素的联合体是复杂的社区，各个联合体成员对整个联合体运作的贡献还不是很清楚。具体地说，从纤维素底物到各种最终产品的碳流动还没有被很好地阐明。以前的研究表明，尤其是厌氧微生物，当它们附着在纤维素纤维上生长时，降解纤维素的效率最高。我们建议研究复杂的纤维素降解群落的结构和功能之间的联系。我们的工作假设是，附着的微生物以生物膜的形式生长将促进生态位的形成，这些生态位可以被具有不同生理需求的微生物利用，最终导致更大的代谢多样性，从而有效地降解纤维素。拟议研究的长期目标是获得具有良好特性的混合培养物，具有快速降解纤维素和合成附加值产品的能力。从这样的群落中分离出来的菌株将被用来生产能有效降解纤维素的“设计者联盟”。这些结果将对微生物-基质的基础研究具有重要意义。

As traditional energy supplies become diminished, there is an increasing need for a sustainable production of useful renewable energy. Biological conversion of a plentiful source of energy, plant biomass, to organic fuels, hydrogen, electricity and other useful products, is a viable alternative to fossil fuels. Cellulose, a major component of plant biomass and of cellulosic wastes, can be decomposed by a wide variety of cellulolytic aerobic and anaerobic bacteria and mixed cultures. Microbial cellulose-degrading consortia are complex communities and the contributions of individual consortium members to the functioning of the consortium as a whole are not well understood. Specifically, the carbon flow from the cellulose substrate to various end products is not well elucidated. Previous studies have shown that especially anaerobic microorganisms degrade cellulose most efficiently, when they grow attached to cellulose fibers. We propose to investigate the link between structure and function of complex cellulose degrading communities. Our working hypothesis is that attached microbial growth in the form of a biofilm will facilitate niche formation which can be exploited by microorganisms with different physiological requirements, ultimately leading to a greater metabolic diversity and thus effective cellulose degradation. The long-term objective of the proposed research is to obtain well characterized mixed cultures with the ability to rapidly hydrolyse cellulose and to synthesize value-added products. Strains isolated from such communities will be used to produce "designer consortia" which will efficiently degrade cellulose. The results will be relevant both for fundamental research on microbe-substrate