[Effect of products of thermophilic methane fermentation on the conidial activation and citric acid biosynthesis by the fungus Aspergillus niger].

The effect of products of thermophilic methane fermentation (PTMF) and their hydrolyzates on the conidial germination and citric acid bioysnthesis by the fungus Aspergillus niger when cultivated on the synthetic and molasses media was investigated. An addition of the above products increased the amount of germinated conidia on the synthetic medium by 1.2--2 times and on the molasses medium by 1.1--1.4 times. The citric acid yeild per unit surface area on the two media grew by 60--100% and 10--20%, respectively. Optimal concentration of dry preparations of PTMF was 5--7.5 mg/100 ml and that of their hydrolyzates was 0.5--1.5 ml/100 ml of the medium. An addition of PTMF to the molasses medium resulted both in an increased yeild of citric acid (1500--1700 g/m2/day) and in reduced (by 12--24 hours) time of the biosynthesis process.