Media effects on the growth ofThiobacillus novellus

The growth ofThiobacillus novellus (ATCC 8093) and of a laboratory strain was observed in a mineral salts medium (MSM) and a medium containing a trace metal solution (TMM). The generation time during growth on MSM was found to be almost half the value for growth on TMM (134 min vs 252 min), with overall yields in the latter being about one-third those on MSM. Cultures maintained for 5 weeks in trace metal media exhibited decreased generation times, but no change in overall yields. An increase in glucose concentration resulted in an increased yield but had no effect on generation times. The addition of biotin to either medium resulted in minor decrease in glucose utilization. The omission of the trace metal constituents, individually, usually resulted in shorter generation times and increased growth yields. It is concluded that differences in growth conditions have been responsible for discrepancies in data from some previous studies.