ANAEROBIC BIODEGRADATION OF PARA-TOLUENE SULFONIC ACID, SULFANILIC ACID AND THIOPHENE-2-ACETIC ACID BY THE SULFATE REDUCING BACTERIUM DESULFOVIBRIO PSYCHROTOLERANS, STRAIN JS1~T IN LIQUID CULTURES, SOIL AND SLUDGE MICROCOSMS

摘要

A sulphate reducing bacterium Desulfovibrio psychrotolerans, strain JS1~T could biodegrade three aromatic sulphur compounds namely p-toulene sulfonic acid (PTSA), Sulfanilic acid (SFA) and Thiophene -2-acetic acid (TPA) when provided as sole source of carbon under strict anaerobic conditions. The biodegradation of these compounds was studied using spectrophotometer and HPLC. The strain JS1~T could grow in 25 mM and could tolerate (with feeble growth) up to 50 mM of all the three test compounds supplemented as sole carbon source however, optimum growth was at 3 or 4 mM concentration. Though none of the tested compounds were completely metabolised within the experimental period of three months, PTSA was degraded up to 82%, SFA up to 65.5% and TPA was degraded up to 72% in liquid culture. The soil and sludge microcosm studies conducted with a) the pure culture of strain JS1~T alone and b) Strain JS1~T along with native microbiota (as consortium) revealed that strain JS1~T could degrade the test compounds more efficiently as pure culture when compared to that with its consortium. The role of native microorganisms in degradation of these compounds was insignificant. The biodegradation of PTSA and TPA was significantly reduced in sludge microcosm when compared to that in soil while, SFA degradation was similar in both soil and sludge microcosms the reasons for which are unknown. A 66%, 38% degradation of PTSA, 65%, 64% degradation of SFA and 72%, 31% degradation of TPA was noted in soil microcosm and in sludge microcosm respectively by the pure culture of JS1~T . The present work in laboratory scale is a preliminary study conducted at ambient, natural conditions of soils and sludge which thus indicated the potential of D. psychrotolerans, strain JS1~T for biodegradation of contaminated soils and sludge, which could be potentially useful in bioremediation of contaminated soils.