RESUMEN
ABSTRACT The purpose of this research was to enhance the production of vitamin K2 by fermentation optimization and Arachis hypogaea supplementation in Flavobacterium sp. mutant SP-L-01. Optimized culture condition were as follows: 6-days shake-flask culture at 37oC with initial pH value 7.0 ± 0.2, shaking speed in 120 r/min and medium volume of 30 mL with 2% inoculums. After optimization of fermentation medium by response surface methodology (RSM), optimized medium were maltose 23.8 g/l, glucose 9.69 g/l, beef extract 15 g/l, K2HPO4 4.5 g/l，NaCl 3.0 g/l and MgSO4·7H2O 0.3 g/l. Production of vitamin K2 after optimization reached to 10.97 mg/l, which is 79.25% higher than that before optimization (6.12 mg/l). 3 mg/mL of arachis hypogaea was added into the medium at 72 h of shake-flake cultivation, which improved the production of menaquinone-4 (MK4) up to 371% and menaquinone-6 (MK6) up to 149% higher than those of the original medium. D-(+)-catechin, one of the components of arachis hypogaea, was added alone into the medium, which also improved the vitamin K2 synthesis.
RESUMEN
The aim of this study was to enhance the production of vitamin K2 by using N-methyl-N-nitro-N-nitroso-guanidine (NTG) and low energy ion beam implantation and optimizing the fermentation medium. Mutation resulted in 1.66-fold higher production of vitamin K2 than that of the parentl strain. The production by the mutant BN-P15-11-1was increased 55% and reached 3.593±0.107 mg/L by using the Plackett-Burman and Box-Behnken designs to optimize the fermentation medium. The optimal fermentation culture medium was composed of (g/L) glycerol 69.6, sucrose 34.5, K2HPO4 4.0, peptone 20, yeast extract 25 and fermented at 37 °C and 150 rpm for 72 h. The results showed that the NTG and low energy ion beam implantation mutations and optimizing fermentation medium were effective methods to enhance vitamin K2 production.