Using mixed anaerobic communities to convert low value biomass into hydrogen

目前对微生物产氢的研究主要集中在纯培养和混合培养上。对纯培养物的研究利用无菌底物来防止污染。对于使用纯培养的工艺来说，底物灭菌是一个主要缺点。能够利用非无菌饲料的微生物培养可以更灵活和更具成本效益。低价值的农业残渣，如玉米秸秆和小麦秸秆，可能是非无菌饲料的来源。含有产酸菌、产乙酸菌和产甲烷菌的混合培养物可以消耗来自低价值农业残渣的糖。然而，与持续产氢相关的一个主要问题是混合厌氧群落中存在耗氢生物体。拟议的研究将重点放在使用长链脂肪酸(LCFA)来抑制氢消费群体。该研究计划为研究和开发利用低价值农业剩余物生产氢气的厌氧工艺提供了概要。短期目标将确定影响氢气生产的环境和工艺参数。将进行批量研究，以考察几种长链脂肪酸(LCFA)对戊糖和己糖发酵的影响。在间歇和连续流动试验中，添加低碳源脂肪酸将通过灭活无芽胞的耗氢微生物和选择更有利的产氢细菌来提高产氢能力。长期目标的主旨将侧重于开发一个可持续的连续制氢系统。

Current research on microbial hydrogen production is focused on using pure and mixed cultures. Studies with pure cultures have utilized sterile substrates to prevent contamination. Substrate sterilization is a major disadvantage for processes using pure cultures. Microbial cultures which are able to utilize non-sterile feedstocks could be more flexible and cost effective. Low value agriculture residues such as corn stover and wheat stalks are possible sources of non-sterile feedstocks. Mixed cultures containing acidogens, acetogens and methanogens can consume sugars derived from low value agriculture residues. However, a major concern related to sustained hydrogen production is the presence of hydrogen consuming organisms in mixed anaerobic communities. The proposed research will focus on using long chain fatty acids (LCFAs) to inhibit the hydrogen consuming population. The research plan provides an outline for investigating and developing an anaerobic process for producing hydrogen using low value agriculture agriculture residues. The short-term objectives will identify environmental and process parameters affecting hydrogen production. Batch studies will be conducted to examine the effect of several long chain fatty acids (LCFAs) on the fermentation of pentose and hexose sugars. Adding LCFAs will be employed to increase hydrogen production by inactivating non-spore forming hydrogen consuming organisms and selecting the more favorable hydrogen producing bacteria in both batch and continuous flow studies. The major thrust of the long-term objectives will focus on developing a sustainable continuous system to generate hydrogen.