Mutation of Gluconobacter oxydans and Bacillus megaterium in a two-step process of l-ascorbic acid manufacture by ion beam

Abstract

Aim: To increase the transformation rate of L L-sorbose to 2-keto-L L-gulonic (2-KLG) acid in a two-step process of L L-ascrobic acid manufacture by ion beam. Methods and Results: Gluconobacter oxydans (GO29) and Bacillus megaterium (BM80) were used in the present study. Ion implantation was carried out with the heavy ion implantation facility at the institute of Plasma Physics in China. 2-KLG in whole culture broth was determined by iodometry. Mutants were screened by singlecolony isolation and 2-KLG accumulation in broth. GO29 and BM80 were implanted by either hydrogen ions (H + ) or nitrogen ions (N + ) with various doses, respectively. The average transformation rate of GM112-302 bred by ion beam in Gram-molecule was increased from 79AE3 to 94AE5% after eight passages in shaking flasks. Furthermore, in 180-ton fermentors in Jiangsu Jiangshan Pharmaceutical Co. Ltd, the transformation rate was stable at 92AE0%, indicating a producer could get 0AE99 kg of gulonic acid from 1AE0 kg of sorbose. Conclusion: Ion beam as a new mutation source had potential advantages in breeding. Comparing with original mixture GO29 and BM80, GM112-302 is more efficient in accumulating 2-KLG, especially at the later phase. Significance and Impact of the Study: GM112-302 bred by ion beam implantation dramatically increased the transformation rate by 19AE2%, which greatly increased efficiency and reduced the cost of L L-ascorbic acid manufacture in a two-step process.

Screening of lipid high producing mutant from rhodotorula glutinis by low ion implantation and study on optimization of fermentation medium

“…, He ? , and it was the most common ion used in ion beam implantation [13]. For ion implantation, mutation frequency and screen efficiency are closely related to the energy and the doses of ions [14].…”

Metabolic Engineering of Microorganisms for Vitamin C Production

“…Studies have showed that both internal and external metabolites from B. megaterium , through biochemical and molecular methods and certain proteins or amino acids, play a role in this process Zhao et al 2008 ) . Further research has shown that B. megaterium secretes two kinds of proteins of about 30-50 kDa and >100 kDa that improve K. vulgare growth and increase 2-KLG productivity (Lu et al 2003 ;Xu et al 2004 ;Zhao et al 2008 ) . However, researchers have not speci fi cally determined which proteins play a role in promoting K. vulgare growth and 2-KLG production.…”

History of Industrial Biotechnology

“…In another process, D -glucose was converted to 2,5 -diketo -D -gluconic acid by Erwinia or Acetobacter which was then transformed into 2 -KLGA by Corynebacterium [99] . Another similar process involved mutants of G. oxydans and Bacillus megaterium [100] . A genetically engineered strain of Erwinia herbicola produced 120 g/l of 2 -KLGA [101], whereas recombinant G. oxydans made 130 g/l [102] .…”