微生物高细胞密度培养技术及其在食品添加剂生产中的应用

High cell density culture of microorganisms and its application in food additives production

微生物高细胞密度培养具有减少培养体积、强化下游分离提取、缩短生产周期和减少设备投资等优点,已成为生化工程领域重点关注的研究课题之一,并在食品添加剂生产中逐步得到广泛应用。一些限制性因素如限制性底物、生长抑制性物质、溶解氧和发酵液流变学特性等,对高细胞密度培养的影响显著;选择合适的生物反应器,包括传统搅拌式生物反应器、气升式生物反应器以及新型的膜生物反应器和透析反应器等,是实现高细胞密度培养的保证;采取适当的培养控制策略,包括基于恒溶解氧、恒pH值、CO2释放速率、底物浓度和呼吸熵的反馈控制策略以及预设参数的非反馈控制策略,是实现高密度培养的关键。本文综述了高细胞密度培养的限制因素、生物反应器及培养控制策略方面的近期研究进展,介绍了该技术在虾青素、脂肪酶、植酸酶、二十二碳六烯酸、α-乙酰乳酸脱羧酶和L-乳酸等食品添加剂生产中的应用,并对微生物高细胞密度培养技术的发展前景进行了展望。

High cell density culture （HCDC） could decrease the fermentation size, benefit the downstream separation process, shorten the total production period, and decrease the equipment investment. Nowadays, HCDC has been attracted the attentions in the biochemical engineering fields, and widely applied in the food additives production. Some limited factors including substrates, inhibitory compositions, dissolved oxygen concentration and broth rheological prop- erties has the direct influence on the outputs of HCDC. Selection of a favorable fermentor including typical stirred or air- lift bioreactors, and recently - developed membrane or dialysis bioreactors is another critical factor for HCDC, and the operation strategies including the feedback control on the basis of the DO - stat, pH - stat, CO2 emission, substrate- concentration or respiratory quotient, and the non - feedback control also affect HCDC process significantly. This re- view summarized the recent research progress in the limited factors, bioreactors and operation control strategies of the high cell density culture, presented the examples of its application in the food additives production including astaxan- thin, lipase, phytase, docosahexaenoic acid, α- acetolactate decarboxylase and L - lactic acid, and finally predicted the prospects of high cell density culture technology.