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高糖和氮源对鼠李糖乳杆菌(Lactobacillus rhamnosus)L-乳酸发酵的影响
Effects of high sugar concentration and nitrogen sources on L-lactic acid fermentation using Lactobacillus rhamnosus
【摘要】 鼠李糖乳杆菌经实验室耐高糖高酸选育,能够在高糖浓度下高效高产L-乳酸。以酵母粉为氮源和生长因子,葡萄糖初始浓度分别为120 g/L和146 g/L,摇瓶培养120h,L-乳酸产量分别为104g/L和117.5g/L,L-乳酸得率分别为86.7%和80.5%。高葡萄糖浓度对菌的生长和乳酸发酵有一定的抑制。增加接种量,在高糖浓度发酵条件下,可以缩短发酵时间,但对增加乳酸产量效果不明显。乳酸浓度对鼠李糖乳杆菌生长和产酸有显著的影响。初始乳酸浓度到达70g/L以上时,鼠李糖乳杆菌基本不生长和产酸,葡萄糖消耗也被抑制。酵母粉是鼠李糖乳杆菌的优良氮源,使用其它被测试的氮源菌体生长和产酸都有一定程度的下降。用廉价的黄豆粉并补充微量维生素液,替代培养基中的酵母粉,可以使产酸浓度和碳源得率得以基本维持。
【Abstract】 A homofermentative strain,Lactobacillus rhamnosus was domesticated to produce L-lactic acid with high(efficiency) and productivity under high sugar and lactic acid(concentrations).After 120 h of fermentation in flasks,using yeast extract as the nitrogen source and growth factors,120 g/L and 146 g/L of glucose were converted to L-lactic acid of 104 g/L,and 117.5 g/L,respectively.At high sugar concentration,the increasement of inoculation volume from 5% to 15 %,reduced the fermentation period but the L-lactic acid production was not obviously increased.The initial lactic acid(concentration) over 30 g/L strongly inhibited the cell growth and L-lactic acid production.When initial lactic acid(concentration) was increased to 70 g/L,cell growth and L-lactic acid production were completely stopped.Yeast extract was the best nitrogen source,while the other tested nitrogen sources reduced the cell growth and lactic acid production.Cheap soybean flour supplemented with a mixture of vitamins could replace the relatively expensive yeast extract in culture(medium) for maintaining the level of L-lactic acid production.
- 【文献出处】 工业微生物 ,Industrial Microbiology , 编辑部邮箱 ,2006年04期
- 【分类号】TQ922.9
- 【被引频次】14
- 【下载频次】473