Degradation kinetics and metabolites in continuous biodegradation of isoprene

The kinetic parameters of isoprene biodegradation were studied in a bioreactor, comprising of bioscrubber and polyurethane foam packed biofilter in series and inoculated with Pseudomonas sp., using a Michaelis-Menten type model. The maximum elimination capacity, ECmax; substrate constant, Ks and ECmax/Ks values for bioscrubber were found to be 666.7 g m−3 h−1, 9.86 g m−3 and 67.56 h−1, respectively while those for biofilter were 3333 g m−3 h−1, 13.96 g m−3 and 238.7 h−1, respectively. The biofilter section exhibited better degradation efficiency compared to the bioscrubber unit. Around 62-75% of the feed isoprene got converted to carbon dioxide, indicating the efficient capability of bacteria to mineralize isoprene. The FTIR and GC-MS analyses of degradation products indicated oxidative cleavage of unsaturated bond of isoprene. These results were used for proposing a plausible degradation pathway for isoprene.