文献类型：期刊文献

英文题名：Effect of pH, glucoamylase, pullulanase and invertase addition on the degradation of residual sugar in L-lactic acid fermentation by Bacillus coagulans HL-5 with corn flour hydrolysate

作者：Lv, Xiangyun[1];Yu, Bo[1];Tian, Xiwei[1];Chen, Yu[1];Wang, Zejian[1,2];Zhuang, Yingping[1,2];Wang, Yonghong[1,2]

机构：[1]E China Univ Sci & Technol, State Key Lab Bioreactor Engn, POB 329,130 Meilong Rd, Shanghai 200237, Peoples R China;[2]Shanghai Inst Biomfg Technol & Collaborat Innovat, POB 329,130 Meilong Rd, Shanghai 200237, Peoples R China

年份：2016

卷号：61

起止页码：124

外文期刊名：JOURNAL OF THE TAIWAN INSTITUTE OF CHEMICAL ENGINEERS

收录：;EI(收录号：20160601899237);WOS:【SCI-EXPANDED(收录号:WOS:000373417400015)】；

基金：This work was financially supported by grants from Major State Basic Research Development Program of China (2013CB733600), the National High Technology Research and Development Program (2015AA021005) and the National Natural Science Foundation of China (Grant No. 31200024).

语种：英文

外文关键词：pH; Hydrolases addition; Residual sugar; L-Lactic acid; Bacillus coagulans; Corn flour hydrolysate

摘要：For commercial lactic acid production, a considerable amount of time (phase II) is required for the depletion of residual sugar to an acceptable range after glucose exhaustion. In this study, the effects of pH, glucoamylase, pullulanase and invertase addition on the degradation of residual sugar were investigated. When pH value in phase II was controlled at 5.4, 5.7, 6.0, 6.3 and 6.5, respectively, pH 6.5 was found to be optimal for residual sugar consumption, and the residual total sugar decreased to 3.74 g/L from 5.02 g/L under normal conditions. Addition of 125 U/mL of glucoamylase and 1.25 U/mL of invertase to the medium further reduced the residual sugar, particularly after lactic acid production ending, while pullulanase addition had no effect. Accordingly, we developed a combined strategy that using the unsterilized hydrolysate, adding invertase at the beginning of phase II and maintaining pH at 6.5 in phase II to reduce residual sugar content. Under these conditions, the residual total sugar and reducing sugar decreased to 1.45 and 1.01 g/L, respectively, 71.12 and 58.94% lower than these obtained under normal conditions. These improvements will reduce costs and facilitate industrial application. (C) 2016 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.