Enhanced Production of Acarbose and Concurrently Reduced Formation of Impurity C by Addition of Validamine in Fermentation ofActinoplanes utahensisZJB-08196

Abstract

Commercial production of acarbose is exclusively via done microbial fermentation with strains from the genera of Actinoplanes. The addition of C7N-aminocyclitols for enhanced production of acarbose and concurrently reduced formation of impurity C by cultivation of A. utahensis ZJB-08196 in 500-mL shake flasks was investigated, and validamine was found to be the most effective strategy. Under the optimal conditions of validamine addition, acarbose titer was increased from 3560 ± 128 mg/L to 4950 ± 156 mg/L, and impurity C concentration was concurrently decreased from 289 ± 24 mg/L to 107 ± 29 mg/L in batch fermentation after 168 h of cultivation. A further fed-batch experiment coupled with the addition of validamine (20 mg/L) in the fermentation medium prior to inoculation was designed to enhance the production of acarbose. When twice feedings of a mixture of 6 g/L glucose, 14 g/L maltose, and 9 g/L soybean flour were performed at 72 h and 96 h, acarbose titer reached 6606 ± 103 mg/L and impurity C concentration was only 212 ± 12 mg/L at 168 h of cultivation. Acarbose titer and proportion of acarbose/impurity C increased by 85.6% and 152.9% when compared with control experiments. This work demonstrates for the first time that validamine addition is a simple and effective strategy for increasing acarbose production and reducing impurity C formation.

Enhancement of acarbose production by genetic engineering and fed-batch fermentation strategy in Actinoplanes sp. SIPI12-34

“…The addition of S-adenosylmethionine [ 41 ] and validamine [ 42 ] to the culture and fermentation at an elevated osmolality [ 43 ] had been demonstrated to promote the production of acarbose. In addition, a series of optimizations were made to the fermentation process by constructing a genome-scale metabolic model of Actinoplanes sp.…”

Enhancement of acarbose production by rational genetic engineering and process optimization in Actinoplanes sp. SIPI12-34

“…The addition of S-adenosylmethionine [39] and validamine [40] to the culture and fermentation at an elevated osmolality [41] had been demonstrated to promote the production of acarbose. In addition, a series of optimizations were made to the fermentation process by constructing a genome-scale metabolic model of Actinoplanes sp.…”

Reconstruction and in silico analysis of an Actinoplanes sp. SE50/110 genome-scale metabolic model for acarbose production

“…Actinoplanes sp. SE50 was screened from soil by Bayer AG (Frommer et al, 1977 ), and other strains went through laborious, conventional mutagenesis and screening, followed by fermentation optimization (Choi and Shin, 2003 ; Wang et al, 2011 ; Xue et al, 2013 ; Cheng et al, 2014 ). Because maltose has been reported to be a moiety of acarbose, which was directly attached to dTDP-acarviose-7-P, and it worked as a carbon source, the carbon sources for Actinoplanes sp.…”

“…It is worth noting that in strain Actinoplanes utahensis ZJB-08196, which was developed from Actinoplanes sp. through ion beam implantation, acarbose production reached 6606 mg/L after optimization of the medium composition and culture conditions (Wang et al, 2011 ), such as maintaining an elevated osmolality via intermittent feeding of necessary components (14.0 g/L maltose, 6.0 g/L glucose, and 9.0 g/L soybean meal, with feeding at 48, 72, 96, and 120 h and a feed volume of 5 mL) (Wang et al, 2012 ), as well as the addition of S-adenosylmethionine (12 h post-inoculation, 100 μmol/L S-adenosylmethionine) (Sun et al, 2012 ) and validamine (prior to inoculation, 20 mg/L) (Xue et al, 2013 ). It is the highest titer of fermentation by A. utahensis until now.…”