Enhanced ε-poly-L-lysine production by improving cellular activity during fermentation

Abstract:

Abstract:［Objective］ To assess the effect of cellular activity on ε-poly-l-lysine (ε-PL) biosynthesis and thereby to rationally improve the production，we studied the cellular activity，ε-PL formation and other parameters cross flask fermentation by Streptomyces ahygroscopicus． ［Methods］Laser scanning confocal microscopy and a colorimetric method were used to determine cellular activity using BacLight Live /Dead and 5-cyano-2，3-ditolyl tetrazolium chloride (CTC) as viable stains． To enhance the activity of the cells in the ε-PL production period，yeast extract was added．［Results］During ε-PL submerged fermentation in flasks，most cells were active in the growth period (0－16 h); cells had metabolic activity in the growth and earlier ε-PL production periods between 0 and 30 h fermentation．Almost no activity was detected after 48 h fermentation when no ε-PL was produced． The improved fermentation achieved 2.24 g/L ε-PL from 1.04 g/L．［Conclusion］Biosynthesis of ε-PL can be boosted by up-regulating cell activity in its production phase.

Key words:Keywords: Streptomyces ahygroscopicus，ε-poly-L-lysine，liquid fermentation，cellular activity，biosynthesis，control fermentation