Biodegradation of phenol substances by pure and mixed culture

The microbial degradation of phenol substances by mixed and pure cultures o f Alcaligenes xylosoxidans and Klebsiella pneumoniae was studied. The pheno l-degrading mixed culture containing two bacterial strains was isolated fro m wastewater of refinery plant. Enrichment culture contained phenol (7.10(- 3) M) as a sole of carbon and energy source. The highest growth of mixed cu lture was observed in phenol concentration 0.5 g/L. A further increase of p henol dose in cultivation medium from 0.5 to 1.0 g/L caused the inhibition of growth. The pure A. xylosoxidans culture utilised phenol as a sole sourc e of carbon only slightly. The growth of K. pneumoniae was not observed whe n phenol was in cultivation medium at concentration range 0.15-0.5 g/L. The most suitable substrate of the tested phenol substances for microbial cons ortium and pure cultures was catechol followed by hydroqiunone and resorcin ol. The positive effect of substrate concentration (0.15-0.5 g/L) on growth of micro-organisms was confirmed. In most cases the biodegradation capabil ity increased in following order: K. pneumoniae, A. xylosoxidans and a mixe d culture at concentration of substrates 0.5 g/L. At lower concentrations o f phenol substances in cultivation medium the order of biodegradation capac ity showed some change. The results indicate that biodegradation of phenol substances demands complementary metabolic diversity and special properties of individual cultures in consortium.