An improved screening method for microorganisms able to convert crude glycerol to 1,3-propanediol and to tolerate high product concentrations
An improved screening method for microorganisms able to convert crude glycerol to 1,3-propanediol and to tolerate high product concentrations
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DOI：
10.1007/s00253-011-3594-7
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发表时间：
2012-02-01
影响因子：
5
通讯作者：
Vorlop, Klaus-Dieter
中科院分区：
文献类型：
--
作者：
Ringel, Anne Katrin;Wilkens, Erik;Vorlop, Klaus-Dieter
为筛选转化粗甘油生产1，3-丙二醇的高效菌株，建立了一种新的筛选方法。三个土壤样品棕榈油丰富的栖息地进行了调查，使用德国生物柴油厂的粗甘油。通过对9株1，3-丙二醇产生菌的筛选，发现了9株1，3-丙二醇产生菌，并通过pH缓冲体系，实现了1，3-丙二醇浓度的快速测定，最高可达40 g L-1。三个菌株表现出非常高的产品耐受性，并被确定为丁酸梭菌。两种菌株AKR 91 b和AKR 102 a在60 g L-1初始1，3-丙二醇存在下生长并产生1，3-丙二醇，菌株AKR 92 a甚至在77 g L-1 1 1，3-丙二醇存在下生长并产生1，3-丙二醇。菌株AKR 91 b和AKR 102 a耐受高达150 g L-1的粗甘油，并产生80%的1，3-丙二醇从相同浓度的纯甘油获得。选择生产菌株的进一步标准是致病性（风险等级）、在低成本培养基上生长的能力，例如，在一个实施例中，酵母抽提物含量少，具有较强的鲁棒性。例如，在一个实施例中，经过多次生物转化后的工艺稳定性。总的来说，菌株C.丁酸菌AKR 102 a由于其在pH调节的生物反应器中的高生产率和高最终浓度而被选择用于进一步的工艺优化和放大。
A new screening method was developed and established to find high-performance bacteria for the conversion of crude glycerol to 1,3-propanediol. Three soil samples from palm oil-rich habitats were investigated using crude glycerol of a German biodiesel plant. Nine promising 1,3-propanediol producers could be found. Because of a special pH buffer system, a fast evaluation on microscale and high 1,3-propanediol concentrations up to 40 g L-1 could be achieved. Three strains demonstrated very high product tolerance and were identified as Clostridium butyricum. Two strains, AKR91b and AKR102a, grew and produced 1,3-propanediol in the presence of 60 g L-1 initial 1,3-propanediol, the strain AKR92a even in the presence of 77 g L-1 1,3-propanediol. The strains AKR91b and AKR102a tolerated up to 150 g L-1 crude glycerol and produced 80% of the 1,3-propanediol attained from pure glycerol of the same concentration. Further criteria for the choice of a production strain were the pathogenicity (risk class), ability to grow on low-cost media, e. g., with less yeast extract, and robustness, e. g., process stability after several bioconversions. Overall, the strain C. butyricum AKR102a was chosen for further process optimization and scale-up due to its high productivity and high final concentration in a pH-regulated bioreactor.