Production of Androstenedione Using Immobilized Mycobacterium sp. via Cryogel Beads in Systems Containing Deep Eutectic Solvents
1. College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China;
2. State Key Laboratory Breeding Base of Green Chemistry Synthesis Technology, College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310032, China
Abstract：The whole-cell side-chain cleavage of phytosterols by Mycobacterium sp. is known as an environmentally friendly method for the production of androstenedione (AD), which is an important intermediate to produce steroids. However, AD yield was limited by factors such as low water solubility of phytosterols, product inhibition and degradation. Deep eutectic solvents (DESs) have been employed as a kind of popular green solvent with the ability to promote substrate dissolution and increase product yield. In this paper, the biotransformation of phytosterols by immobilized Mycobacterium sp. resting cells in systems containing DESs was investigated, and 3 batches of semi-continuous biotransformation were performed. First, two types of DESs, i.e. betaine/maltose and betaine/galactose, were prepared to construct solvent systems, and the cryogel beads polymerized with 2-hydroxyethyl methacrylate and butyl methacrylate were used as the carrier of immobilization. With better dispersions and utilization of cells, AD yield per unit of cells was improved to 6.8 times by immobilized cells, and high biotransformation efficiency was still maintained when the addition of immobilized cryogel beads was up to 180 g/L. The AD yield by immobilized cells was further enhanced by the introduction of DESs, which inhibited the AD degradation pathway and reduced the accumulation of AD in the interior of cryogel beads. Finally, high AD yield per unit of cells (401.4 mg/g-DCW) was achieved after 3 batches of semi-continuous biotransformations in the system with 10% Bet/Mal, which was 12 times of that by free resting cells in the buffer system. In summary, AD yield was significantly enhanced due to the improved cell utilization by immobilization of Mycobacterium sp. via cryogel beads combined with the promotion of DESs on biotransformation, which presented a potential industrial application prospect.
HE Jingkai1,XIAO Xia1,LOU Xiaoling2 et al. Production of Androstenedione Using Immobilized Mycobacterium sp. via Cryogel Beads in Systems Containing Deep Eutectic Solvents[J]. 化学反应工程与工艺, 2021, 37(1): 47-54.
