Effects of intermittent addition of cellulase for production of L-lactic acid from wastewater sludge by simultaneous saccharification and fermentation.
Effects of intermittent addition of cellulase for production of L-lactic acid from wastewater sludge by simultaneous saccharification and fermentation.
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DOI：
10.1002/bit.10573
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发表时间：
2003-05
影响因子：
3.8
通讯作者：
K. Nakasaki;T. Adachi
中科院分区：
文献类型：
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作者：
K. Nakasaki;T. Adachi
试图从造纸工业的废水污泥中制备聚乳酸的前体l -乳酸，聚乳酸是一种可生物降解的塑料。污泥中纤维素含量高，需要在纤维素酶的作用下水解成葡萄糖，然后再用乳酸菌处理。为此，研究了同时糖化发酵（SSF）方法。社保基金的最佳pH值为生产乳酸的新孤立的乳酸细菌具有高选择性L-lactic酸被发现在pH = 5.0,和最适温度约40度c的基础上测量细胞的密度变化的乳酸细菌,是确定细菌活动可能会持续在高水平相对较长一段时间,纤维素酶的快速失活降低了l -乳酸的产量。为了补偿纤维素酶的失活，每天间歇添加一次纤维素酶，在最佳pH和温度条件下，根据污泥中潜在葡萄糖含量，L-乳酸的最大浓度达到16.9 g/L，即产量为72.2%。
An attempt was made to create L-lactic acid, a precursor of poly-lactic acid, which is a biodegradable plastic, from wastewater sludge from the paper-manufacturing industry. The sludge contained a high percentage of cellulose and needed to be hydrolyzed to glucose by the action of the cellulase before being treating with lactic acid bacteria. Therefore, a method involving simultaneous saccharification and fermentation (SSF) was carried out. The optimum pH of the SSF for production of the lactic acid by the newly isolated lactic acid bacterium with a high selectively of L-lactic acid was found out to be around pH = 5.0, and the optimum temperature to be approximately 40 degrees C. On the basis of the measurement of the cell density changes in the lactic acid bacteria, it was ascertained that the bacterial activity could continue at a high level for a relatively long period of time, and that the L-lactic acid productivity was diminished by the rapid deactivation of the cellulase. With the intermittent addition of cellulase once daily for the sake of compensating for the cellulase deactivation, the L-lactic acid attained a maximum concentration of 16.9 g/L, i.e., a 72.2% yield based on the potential glucose contained in the sludge under optimum pH and temperature conditions.