Yeast Extract Promotes Cell Growth and Induces Production of Polyvinyl Alcohol-Degrading Enzymes

Table 1

Effects of multiple yeast extract addition on cell growth and PVAases production in flask. Number (1) 2 g yeast extract per liter of culture broth added at 18 h with a volume of 6 mL; number (2) 1 g yeast extract per liter of culture broth added at 18 h and 20 h with a volume of 3 mL each time; number (3) 0.67 g yeast extract per liter of culture broth added at 18 h, 20 h, and 22 h with a volume of 2 mL each time; number (4) 0.50 g yeast extract per liter of culture broth added at 18 h, 20 h, 22 h, and 24 h with a volume of 1.5 mL each time.

No.	Addition time				Experimental results
	18 h	20 h	22 h	24 h	DCW (g/L)	PVAases activity (U/mL)	Specific PVAases activity (kU/g)
	Concentration of yeast extract (g/L)
0	0 (Control)				1.01 ± 0.03	1.08 ± 0.02	1.07 ± 0.02
1	2				1.42 ± 0.03	2.09 ± 0.06	1.47 ± 0.05
2	1	1			1.44 ± 0.03	2.33 ± 0.07	1.62 ± 0.07
3	0.67	0.67	0.67		1.47 ± 0.05	2.88 ± 0.08	1.96 ± 0.06
4	0.5	0.5	0.5	0.5	1.48 ± 0.04	2.99 ± 0.09	2.02 ± 0.07