Fig. 2From: Engineering Streptomyces albulus to enhance ε-poly-L-lysine production by introducing a polyphosphate kinase-mediated ATP regeneration systemEffect of exogenous ATP on cell growth and ε-PL production of S. albulus WG608. The data are presented as averages, and the error bars represent standard deviations (n = 3 independent experiments). *0.01 < P < 0.05, **P < 0.01Back to article page