European Journal of Biomedical and Pharmaceutical Sciences

DIAUXIC GROWTH OF RAOULTELLA SP SBS2 FAVORING ENHANCED DEGRADATION OF PHENOL IN MINERAL SALT PHENOL MEDIUM

*Jayachandran K. and Anoop M.

ABSTRACT

Raoultella sp SBS2 was proved as a potent species capable of degrading phenol to less toxic or non toxic intermediates. The ability of the bacteria to grow at various concentrations of phenol from 7.5mM to 37.5 mM concentrations was evaluated in terms of both growth and percentage reduction of phenol. On analysis of the growth curve, it was observed that the organism exhibited diauxic growth in all the cases of effective biodegradation. The extent of log phase in each of the phases in the diauxic growth pattern decreased upon increasing the concentration of phenol from 7.5 mM to 37.5 mM. The results showed similar trend in the reduction of percentage of phenol biodegradation on raising the concentration from 7.5mM to 37.5 mM. At various concentrations of phenol, the growth pattern showed a better degradation rate in second phase of logarithmic growth rather than in first phase. Phenol concentration of 37.5 mM yielded only one significant lag phase from 4 to 8 hours giving a total phenol removal of only 33% in MSPM.

Keywords: Phenol, Raoultella sp, Diauxic growth, biodegradation.