The Effect of Amino-acids and Glycerol Addition on MK-7 Production

Abstract

Bacillus subtilis natto was fermented at 40 °C for six days in the media consisted of yeast extract 5% (w/v); soy peptone18.9% (w/v); glycerol 5% (w/v) and K2HPO4 0.06% (w/v). Serine, arginine and asparagine as amino acid sources and glycerol as carbon supply were the limiting at the end of fermentation time while total free amino acids concentration increased 1.7 fold during the fermentation period. Addition of 2 % (w/v) glycerol on the second day of fermentation to the medium enhanced the MK-7 production whereas addition of limiting amino acids did not result in higher MK-7 production. This is the first report on identifying the deficient amino acids in MK-7 fermentation and contribution of additional glycerol feeds on enhancing the production in Bacillus subtilis natto.