Institute of Chemical and Engineering Sciences, Agency for Science, Technology and Research (A STAR), 1 Pesek Road, Jurong Island, Singapore.
Appl Microbiol Biotechnol. 2011 Feb;89(4):1255-64. doi: 10.1007/s00253-010-3076-3. Epub 2011 Jan 7.
The rapidly expanding market for biodiesel has increased the supply and reduced the cost of glycerol, making it an attractive sustainable feed stock for the fuel and chemical industry. Glycerol-based biorefinery is the microbial fermentation of crude glycerol to produce fuels and chemicals. A major challenge is to obtain microbes tolerant to inhibitors such as salts and organic solvents present in crude glycerol. Microbial screening was attempted to isolate novel strain capable of growing on crude glycerol as a sole carbon source. The newly isolated bacteria, identified as nonpathogenic Kluyvera cryocrescens S26 could convert biodiesel-derived crude glycerol to ethanol with high yield and productivity. The supplementation of nutrients such as yeast extract resulted in distinguished enhancement in cell growth as well as ethanol productivity under anaerobic condition. When glycerol fermentation is performed under microaerobic condition, there is also a remarkable improvement in cell growth, ethanol productivity and yield, compared with those under strict anaerobic condition. In batch fermentation under microaerobic condition, K. cryocrescens S26 produced 27 g/l of ethanol from crude glycerol with high molar yield of 80% and productivity of 0.61 g/l/h.
生物柴油市场的迅速扩大增加了甘油的供应并降低了其成本，使其成为燃料和化学工业中具有吸引力的可持续原料。基于甘油的生物精炼厂是通过微生物发酵粗甘油来生产燃料和化学品。一个主要的挑战是获得能够耐受粗甘油中存在的盐和有机溶剂等抑制剂的微生物。已经尝试进行微生物筛选，以分离能够以粗甘油为唯一碳源生长的新型菌株。新分离的细菌被鉴定为非致病性克鲁维酵母 S26，能够将生物柴油衍生的粗甘油高效转化为乙醇。在厌氧条件下，添加酵母提取物等营养物质可显著提高细胞生长和乙醇生产力。与严格厌氧条件相比，在微需氧条件下进行甘油发酵时，细胞生长、乙醇生产力和产率也有显著提高。在微需氧条件下进行分批发酵时，K. cryocrescens S26 从粗甘油中生产 27 g/L 的乙醇，具有 80%的高摩尔产率和 0.61 g/L/h 的生产力。
