Kinetic analysis and bacterium metabolization of α-pinene by a novel identified Pseudomonas sp. strain

Biodegradation has become a popular alternative remediation technology for its economic and ecological advantages. An aerobic bacterium (strain ZW) capable of degrading α-pinene was isolated from a biofilter by a selective enrichment. Based on the 16S rRNA gene analysis and physiochemical properties, this strain was identified as Pseudomonas veronii. Under the optimized condition achieved by the response surface methodology (RSM), as well as pH 6.82, temperature 26.3°C and NaCl concentration 1.36%, almost 100% α-pinene could be removed within 45 hr. Enzymatic biodegradation by the crude intracellular enzyme could be described well by the Michaelis-Menten model in which the maximum degradation rate Vmax and the half-saturation constant Km were calculated to be 0.431 mmol/(L·(min) and 0.169 mmol/L, respectively. Activity assay of catechol suggested that the strain ZW possessed a catechol-1,2-dioxygenase and could decompose benzene-ring through ortho ring cleavage. Based on the identified intermediates by GC/MS, a new metabolic pathway was proposed, in which the final metabolites were some simpler organic and inorganic compounds. The present work demonstrated that the strain ZW would have a great application prospect for the remediation of α-pinene-contaminated environment.