Enhanced Production of 6-(N-Hydroxyethyl)-Amino-6-Deoxy-α-L-Sorbofuranose by Immobilized Gluconobacter oxydanson Corn Stover with a pH Control Strategy in a Bubble Column Bioreactor

• Published in: Applied biochemistry and biotechnology Vol. 188; no. 2; pp. 297 - 309
• Main Authors: Hu, Zhong-Ce, Bu, Jia-Li, Wang, Ru-Yi, Ke, Xia, Zheng, Yu-Guo
• Format: Journal Article
• Language: English
• Published: New York Springer US 01-06-2019; Springer Nature B.V
• Subjects: Aeration; Ammonia; Ammonium chloride; Bacteria; Biochemistry; Bioreactors; Biotechnology; Biotransformation; Bubble columns; Chemistry; Chemistry and Materials Science; Corn; Gluconobacter oxydans; Immobilized cells; Miglitol; pH control; pH effects; Sodium hydroxide; Stover; Supplements; Hydroxyethyl)-amino-6-deoxy-α-L-sorbofuranose; Corn stover; Biotransformation; Cell immobilization; 6-; Gluconobacter oxydans; 6-(N-Hydroxyethyl)-amino-6-deoxy-α-L-sorbofuranose
• ISSN: 0273-2289; 1559-0291
• DOI: 10.1007/s12010-018-2924-y

6-(
N
-Hydroxyethyl)-amino-6-deoxy-α-L-sorbofuranose (6NSL) is a key intermediate in the synthesis of miglitol. Biotransformation of
N
-2-hydroxyethyl glucamine (NHEG) to 6NSL was performed by immobilized
Gluconobacter oxydans
, which was prepared by cultivating the cells in a home-made bubble column bioreactor where corn stover particles were loaded. The optimal carrier addition and aeration rate for 6NSL production by immobilized cells in the bioreactor were determined to be 25 g/L and 2.5 vvm respectively. The supplementation of NH
4
Cl was conducive to the biotransformation of NHEG and was performed by adding aqueous ammonia and HCl, which was taken as the pH controlling agents as well. An optimal pH control strategy using the mixture of aqueous ammonia and NaOH was applied, resulting in a 9.9% increased production of 6NSL, while repeated batches of biotransformation increased from three times to four times. Finally, the 6NSL concentration and the conversion rate of NHEG to 6NSLreached 44.2 ± 1.5 g/L and 88.4 ± 2.0%, respectively, in average after four cycles of biotransformation under the optimized condition.