Joint BioEnergy Institute, Emeryville, CA, USA.
J Appl Microbiol. 2012 Dec;113(6):1362-70. doi: 10.1111/jam.12002. Epub 2012 Oct 1.
The aim of the study was to develop an approach to enrich ionic liquid tolerant micro-organisms that efficiently decompose lignocellulose in a thermophilic and high-solids environment.
High-solids incubations were conducted, using compost as an inoculum source, to enrich for thermophilic communities that decompose switchgrass in the presence of the ionic liquid 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc]). Ionic liquid levels were increased from 0 to 6% on a total weight basis incrementally. Successful enrichment of a community that decomposed lignocellulose at 55°C in the presence of 6% [C2mim][OAc] was achieved, when the [C2mim][OAc] level was increased stepwise from 2% to 4% to 5% to 6%. Pyrosequencing results revealed a shift in the community and a sharp decrease in richness, when thermophilic conditions were applied.
A community tolerant to a thermophilic, high-solids environment containing 6% [C2mim][OAc] was enriched from compost. Gradually increasing [C2mim][OAc] concentrations allowed the community to adapt to [C2mim][OAc].
A successful approach to enrich communities that decompose lignocellulose under thermophilic high-solids conditions in the presence of elevated levels of [C2mim][OAc] has been developed. Communities yielded from this approach will provide resources for the discovery of enzymes and metabolic pathways relevant to biomass pretreatment and fuel production.
本研究旨在开发一种方法，以富集能够在高温和高固体环境中有效分解木质纤维素的耐受离子液体的微生物。
使用堆肥作为接种源进行高固体孵育，以富集在离子液体 1-乙基-3-甲基咪唑乙酸盐([C2mim][OAc])存在下分解柳枝稷的嗜热群落。离子液体的浓度按总重量基础从 0 逐步增加到 6%。当离子液体浓度从 2%逐步增加到 4%、5%和 6%时，成功地富集了一种在 55°C 下、6%[C2mim][OAc]存在下分解木质纤维素的群落。测序结果表明，当应用高温条件时，群落发生了变化，丰富度急剧下降。
从堆肥中富集了一种耐受高温、高固体环境并含有 6%[C2mim][OAc]的微生物群落。逐渐增加离子液体浓度允许群落适应[C2mim][OAc]。
本研究成功地开发了一种在高温高固体条件下、离子液体浓度升高的情况下富集能够分解木质纤维素的微生物群落的方法。从该方法中获得的群落将为发现与生物质预处理和燃料生产相关的酶和代谢途径提供资源。
