Development of an interspecies interaction model: An experiment on Clostridium cadaveris and Clostridium sporogenes under anaerobic condition

Abstract

The specific primer and probe sets for quantifying Clostridiwn cadaveris and Clostridium sporogenes using a quantitative real-time PCR were designed. Each primer and probe set detected only the target species very specifically. The two species were cultivated in pure and mixed culture in batch mode with glucose as the only carbon source. The designed QPCR sets were used successfully to estimate the biokinetic parameters of each species in pure culture: i.e., maximum specific growth rate mu(max), half saturation concentration K-s, growth yield Y, and decay coefficient K-d. of C. cadaveris and C. sporogenes were 0.311 +/- 0.020 and 0.360 +/- 0.019 h(-1), 4.241 +/- 1.653 and 5.171 +/- 1.097 g/L, 0.301 +/- 0.065 and 0.199 +/- 0.037 10(11) copies/g, 0.005 0.043 and 0.009 +/- 0.025 h(-1), respectively. The effect of interspecific interaction of on substrate consumption rate and microbial growth was evaluated using mixed culture; curve fitting and comparison of coefficients detected increase in substrate consumption rate but decrease in microbial growth rate; these results imply interspecific interaction effect. A new model was of the interspecific interaction was developed, with focus on accuracy, realism, simplicity and biological significance. This interspecific interaction model may be extended to more complex bioprocesses such as biological wastewater treatment systems and anaerobic digestion.