Biocatalytic conversion of a lactose-rich dairy waste into D-tagatose, D-arabitol and galactitol using sequential whole cell and fermentation technologies.

Guoyan Zhang, Hossain M Zabed, Yingfeng An, Junhua Yun, Jiaqi Huang, Yufei Zhang, Xiaolan Li, Jiangfei Wang, Yuvaraj Ravikumar, Xianghui Qi

Bioresource technology 2022 Aug

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Dairy industry waste has been explored as a cheap and attractive raw material to produce various commercially important rare sugars. In this study, a lactose-rich dairy byproduct, namely cheese whey powder (CWP), was microbially converted into three low caloric sweeteners using whole-cell and fermentation technologies. Firstly, the simultaneous lactose hydrolysis and isomerization of lactose-derived D-galactose into D-tagatose was performed by an engineered Escherichia coli strain co-expressing β-galactosidase and L-arabinose isomerase, which eventually produced 68.35 g/L D-tagatose during sequential feeding of CWP. Subsequently, the mixed syrup containing lactose-derived D-glucose and residual D-galactose was subjected to fermentation by Metschnikowia pulcherrima E1, which produced 60.12 g/L D-arabitol and 28.26 g/L galactitol. The net titer of the three rare sugars was 156.73 g/L from 300 g/L lactose (equivalent to 428.57 g/L CWP), which was equivalent to 1.12 mol product/mol lactose and 52.24% conversion efficiency in terms of lactose. Copyright © 2022 Elsevier Ltd. All rights reserved.

Citation

Guoyan Zhang, Hossain M Zabed, Yingfeng An, Junhua Yun, Jiaqi Huang, Yufei Zhang, Xiaolan Li, Jiangfei Wang, Yuvaraj Ravikumar, Xianghui Qi. Biocatalytic conversion of a lactose-rich dairy waste into D-tagatose, D-arabitol and galactitol using sequential whole cell and fermentation technologies. Bioresource technology. 2022 Aug;358:127422