State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China.
Bioresour Technol. 2011 Oct;102(20):9345-9. doi: 10.1016/j.biortech.2011.07.120. Epub 2011 Aug 10.
The effects of temperature, agitation rate and medium composition, including concentrations of glucose, soybean peptone, and inorganic ions, on pellet formation and pellet diameter of Rhizopus delemar (Rhizopus oryzae) NRRL1526 during pre-culture were studied. Inorganic ions and soybean peptone had negative and positive effects on pellet formation, respectively. The initial glucose and soybean peptone concentrations directly affected pellet diameter. Within a certain range, pellet diameter decreased with increased initial substrate concentrations; however, above this range there was an opposite trend. Thus, optimal concentrations of substrate during pre-culture were beneficial for producing small pellets of R. delemar. Furthermore, dry cell mass and yield of fumaric acid tended to increase with decreased pellet diameter. Based on the pellet morphology optimization, the final fumaric acid concentration was improved by 46.13% when fermented in a flask and 31.82% in stirred bioreactor tank fermentation.
研究了温度、搅拌速度以及包括葡萄糖、大豆蛋白胨和无机离子浓度在内的培养基组成对米根霉（Rhizopus oryzae）NRRL1526 预培养过程中颗粒形成和颗粒直径的影响。无机离子和大豆蛋白胨对颗粒形成有负、正影响。初始葡萄糖和大豆蛋白胨浓度直接影响颗粒直径。在一定范围内，随着初始基质浓度的增加，颗粒直径减小；然而，超过这个范围则出现相反的趋势。因此，预培养过程中最佳的基质浓度有利于产生较小的米根霉颗粒。此外，随着颗粒直径的减小，细胞干质量和延胡索酸产量趋于增加。基于颗粒形态优化，在摇瓶发酵中最终延胡索酸浓度提高了 46.13%，在搅拌式生物反应器罐发酵中提高了 31.82%。
