Microbial co-cultivation: Reaction dynamics of combustible gases bioremediation in goaf

Abstract

The accumulation of combustible gases in goaf is a key and difficult point in mine disaster prevention and control, which can easily lead to coal mine accidents and seriously safety production. Methanotrophs (S2, T7) and carboxydotrophic bacteria (M13) were extracted from mine environment to cocultivation. The cultivation conditions such as inoculation, temperature, and pH were selected to explore the effects of the growth and metabolic characteristics, and reveal the reaction kinetics of mixed strains (S2/M13, T7/M13). The results showed that the optimal inoculation amount for mixed strains was 5 %, and the maximum range of mixed carbon source inoculation for S2/M13 and T7/M13 were 9.69 % CH4+(7.27–9.69 % CO) and 9.69 % CH4+(4.35–7.27 % CO), the optimal cultivation temperatures were 25, 30 ℃, respectively, and the optimal pH was 7. In addition, the CH4 metabolic rates of S2/M13 and T7/M13 were 72.4 % and 85.4 %, respectively, and the CO metabolic rate reached over 95 % under the above optimal conditions, the processes of growth and metabolism of the mix cultures remained consistent. Moreover, the growth curves of the S2/M13 and T7/M13 conformed to the Logistic model, and whose attenuation coefficients (b) were 0.035, −0.215 d−1, the maximum specific growth rates (umax) were 0.524, 0.862 d−1, respectively. At the same time, the reaction rate of combustible gases showed high consistency in the logarithmic and stationary phases of the mixed strains, and exhibited a good linear relationship with the consumption rate of O2, the inhibitory kinetics of mixed strains on the reaction rate of combustible gases under different cultivation conditions were determined. The research results have vital theoretical and practical significance for the prevention and control of combustible gases and the safe mining in coal mines.