Biodegradation of Tertiary Butyl Mercaptan in Water

Abstract

Tertiary butyl mercaptan (TBM) belongs to the alkyl mercaptan family and possesses a characteristic odor. Tertiary butyl mercaptan (TBM) can enter aquatic environments through anthropogenic activities as well as the natural processes. Undefined microbial cultures from different soils along with a pure culture were used to study the biodegradation of TBM in water under aerobic conditions. There were about 17% losses in gas phase TBM concentrations attributed to abiotic losses over the period of 14 days. Environmental microbial consortium from sandy soils with low organic matter content and significantly lower heterotrophs resulted in the lowest biodegradation, only slightly higher than abiotic losses. Microbial cultures isolated from soils with previous contamination history resulted in higher degradation rates. In general, biodegradation of TBM in water followed first-order kinetics. The first-order kinetic constant ranged from 0.002 to 0.005 h -1 . TBM was partly degraded to two significant intermediate products and partly mineralized to CO 2 in water with mixed culture isolated from a petroleum contaminated soil. The half- life of TBM in water with this mixed culture was only six days. A Gram-ve bacterium isolated from a grey-water bioprocessor, Alcaligines faecalis subsp. phenolicus subsp. nov, was able to mineralize 50% of TBM within four days under laboratory conditions. The degradation rate was slightly increased with the addition of tertiary butyl alcohol while slightly inhibited with the addition of phenol.