颗粒状米根霉 NRRL 395 在生物柴油粗甘油上生产 L(+)-乳酸。
L (+)-lactic acid production by pellet-form Rhizopus oryzae NRRL 395 on biodiesel crude glycerol.
机构信息
Food Science and Technology Department, Unit of Chemistry and Biochemistry, University of Agricultural Sciences and Veterinary Medicine, 3-5 Mănăştur str, Cluj-Napoca 400372, România.
出版信息
Microb Cell Fact. 2013 Oct 10;12:92. doi: 10.1186/1475-2859-12-92.
BACKGROUND
Given its availability and low price, glycerol derived from biodiesel industry has become an ideal feedstock for the production of fuels and chemicals. A solution to reduce the negative environmental problems and the cost of biodiesel is to use crude glycerol as carbon source for microbial growth media in order to produce valuable organic chemicals. In the present paper, crude glycerol was used as carbon substrate for production of L (+)-lactic acid using pelletized fungus R. oryzae NRRL 395 on batch fermentation. More, the experiments were conducted on media supplemented with inorganic nutrients and lucerne green juice.
RESULTS
Crude and pure glycerols were first used to produce the highest biomass yield of R. oryzae NRRL 395. An enhanced lactic acid production then followed up using fed-batch fermentation with crude glycerol, inorganic nutrients and lucerne green juice. The optimal crude glycerol concentration for cultivating R. oryzae NRRL 395 was 75 g l(-1), which resulted in a fungal biomass yield of 0.72 g g(-1) in trial without lucerne green juice addition and 0.83 g g(-1) in trial with lucerne green juice. The glycerol consumption rate was 1.04 g l(-1) h(-1) after 48 h in trial with crude glycerol 75 g l(-1) while in trial with crude glycerol 10 g l(-1) the lowest rate of 0.12 g l(-1) h(-1) was registered. The highest L (+)-lactic acid yield (3.72 g g(-1)) was obtained at the crude glycerol concentration of 75 g l(-1) and LGJ 25 g l(-1), and the concentration of lactic acid was approximately 48 g l(-1).
CONCLUSIONS
This work introduced sustainable opportunities for L (+)-lactic acid production via R. oryzae NRRL 395 fermentation on biodiesel crude glycerol media. The results showed good fungal growth on crude glycerol at 75 g l(-1) concentration with lucerne green juice supplementation of 25 g l(-1). Lucerne green juice provided a good source of nutrients for crude glycerol fermentation, without needs for supplementation with inorganic nutrients. Crude glycerol and lucerne green juice ratio influence the L (+)-lactic acid production, increasing the lactate productivity with the concentration of crude glycerol.
背景
鉴于生物柴油产业甘油的易得性和低廉的价格，它已成为生产燃料和化学品的理想原料。解决生物柴油的负面环境问题和成本问题的一种方法是使用粗甘油作为微生物生长培养基的碳源，以生产有价值的有机化学品。在本文中，使用颗粒状真菌 R. oryzae NRRL 395 在分批发酵中使用粗甘油作为碳底物生产 L (+)-乳酸。此外，还在添加无机养分和卢塞恩绿汁的培养基上进行了实验。
结果
粗甘油和纯甘油首先用于生产 R. oryzae NRRL 395 的最高生物量产量。然后，使用粗甘油、无机养分和卢塞恩绿汁进行补料分批发酵，随后进行了增强的乳酸生产。在没有卢塞恩绿汁添加的试验中，最适合培养 R. oryzae NRRL 395 的粗甘油浓度为 75 g l(-1)，得到的真菌生物量产量为 0.72 g g(-1)，而在添加卢塞恩绿汁的试验中为 0.83 g g(-1)。在粗甘油 75 g l(-1)的试验中，甘油消耗率为 1.04 g l(-1) h(-1)，而在粗甘油 10 g l(-1)的试验中，最低消耗率为 0.12 g l(-1) h(-1)。在粗甘油浓度为 75 g l(-1)和 LGJ 25 g l(-1)时，获得了最高的 L (+)-乳酸产量（3.72 g g(-1)），乳酸浓度约为 48 g l(-1)。
结论
本工作通过在生物柴油粗甘油培养基上发酵 R. oryzae NRRL 395，为 L (+)-乳酸生产带来了可持续的机会。结果表明，在添加 25 g l(-1)卢塞恩绿汁的情况下，75 g l(-1)浓度的粗甘油对真菌生长良好。卢塞恩绿汁为粗甘油发酵提供了良好的养分来源，无需添加无机养分。粗甘油和卢塞恩绿汁的比例影响 L (+)-乳酸的生产，随着粗甘油浓度的增加，乳酸的生产力增加。
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