Characteristics of scale-up fermentation of mixed methane-oxidizing bacteria

The mixed methane-oxidizing bacteria, which can keep the unique catalytic properties of methanotrophs and overcome the general limitations of slow growth and low activity of the pure methanotrophic culture, have promising applications for biotechnology. In this study, scale-up fermentation for the mixed methane-oxidizing bacteria was carried out from 5 L (working volume 3 L) to 100 L (working volume 65 L) and then to 600 L (working volume 350 L) fermenter, and the mixed bacterial concentration with 2.69 g L−1 dry cell weight was obtained in a 600 L fermenter after 25 h culture. The existence of the coexisting bacteria together with methanotrophs could make a positive contribution to the bacterial growth and MMO activity of the mixed culture. During the scale-up cultivation, the growth, methane-oxidizing capacity, and community of the mixed bacteria were maintained, indicating that it would be possible for large-scale preparation of the mixed methane-oxidizing bacteria.