Ansari Faranak, Nouri Hoda, Moghimi Hamid
Department of Microbiology, School of Biology, College of Science, University of Tehran, Tehran, 1417864411, Iran.
Department of Systems Biotechnology, Institute of Industrial and Environmental Biotechnology, National Institute for Genetic Engineering and Biotechnology (NIGEB), Tehran, Iran.
Microb Cell Fact. 2024 Dec 27;23(1):348. doi: 10.1186/s12934-024-02629-1.
Vitamin K2 is an essential nutrient for blood coagulation and cardiovascular health and mainly produced by bacteria strain like B. subtilis. researchers have explored producing strain improvement, cultivation mode, environmental optimization, increased secretion, and using cheaper carbon and nitrogen sources in order to increase vitamin K2 productivity. This study examines the impact of varioius concentration of soapstock, which is a by-product of vegetable oil refining, as an alternative carbon source with lower pirce, in the fermentation medium instead of glycerol on the microbial synthesis of vitamin K2 using B. subtilis natto ATCC 23857.
The results demonstrate that when the glycerol in fermentation medium was substituted with soapstock, by 75% concentartion, the fermentation process produced a yield of 158.16 mg/L of vitamin K2 after 72 h; This was 3.8 times more than the control medium containing glycerol. When the entire culture medium was replaced with wastewater, the vitamin K2 concentration reached 21.18 mg/L, 52% of the control medium's concentration. If the carbon sources in the fermentation medium consisted of 20% soapstock and 47.4 g/L glycerol (maintaining the same final glycerol concentration as the control medium), the vitamin K2 concentration reached 35.7 mg/L or 85.8% of the control medium. The analysis of soapstock fermentation medium characteristics reveals that after fermentation with B. subtilis, the COD of soapstock fermentation medium was dramatically reduced from 259,500 mg/L to 57,830 mg/L.
Using soapstock as an alternative carbon source for fermentation did not negatively impact the bioprocess and increased vitamin K2 production. Therefore, this research introduces an alternative carbon resource for vitamin K2 production and paves the way for the biorefinement of soapstock.
维生素K2是血液凝固和心血管健康所必需的营养素，主要由枯草芽孢杆菌等菌株产生。研究人员探索了生产菌株改良、培养模式、环境优化、增加分泌以及使用更便宜的碳源和氮源等方法，以提高维生素K2的产量。本研究考察了植物油精炼副产物皂脚作为价格较低的替代碳源，在发酵培养基中替代甘油，对纳豆芽孢杆菌ATCC 23857微生物合成维生素K2的影响。
结果表明，当发酵培养基中的甘油被75%浓度的皂脚替代时，发酵72小时后维生素K2产量达到158.16mg/L；这比含有甘油的对照培养基高出3.8倍。当整个培养基被废水替代时，维生素K2浓度达到21.18mg/L，为对照培养基浓度的52%。如果发酵培养基中的碳源由20%的皂脚和47.4g/L甘油组成（保持与对照培养基相同的最终甘油浓度），维生素K2浓度达到35.7mg/L，即对照培养基的85.8%。对皂脚发酵培养基特性的分析表明，用枯草芽孢杆菌发酵后，皂脚发酵培养基的化学需氧量从259500mg/L大幅降至57830mg/L。
使用皂脚作为发酵的替代碳源对生物过程没有负面影响，且提高了维生素K2的产量。因此，本研究为维生素K2生产引入了一种替代碳源，并为皂脚的生物精炼铺平了道路。
