Antimicrobial activity of steady state cultures of Bacillus sp CCMI 1051 against wood contaminant fungi

Abstract

The effect of changing dilution rate (D) on Bacillus sp. CCMI 1051 at dilution rates between 0.1 and 0.55 h−1 in a glucose-limited medium was studied. Biomass values varied between 0.88 and 1.1 g L−1 at D values of 0.15–0.35 h−1. Maximal biomass productivity was found to be 0.39 g L−1 h−1, obtained at D= 0.35 h−1 and corresponding to a 54.4% conversion of the carbon into cell mass. The highest rate of glucose consumption was 4.45 mmol g−1 h−1 occurring at D= 0.4 h−1. The glucose concentration inside the chemostat was below the detection level starting to accumulate around 0.4 h−1. Growth inhibition of fifteen strains of fungi by the broth of the steady-state cell-free supernatants was assessed. Results showed that the relative inhibition differ among the target species but was not influenced by the dilution rate changing.