PEROXIDASE, LACCASE EXTRACELLULAR ENZYME RODUCTION AND DEGRADATION OF AROMATIC COMPOUNDS BY ACTINOMYCETE XKBH1 STRAIN

Abstract

Four actinomycete strains include XKBH1, XKBH2, XKBH3, XKBH5 were isolated from herbicide contaminated soil at Bien Hoa Airport. They showed ability to produce laccase with initial activity was low. The XKBH1 strain was identified as  Streptomycessp. based on 16S rRNA coding gene equence analysis. The sequence of16S rRNA gene (approximately 1489 bp) was deposited in the GeneBank with assession number GQ 204110. Strain XKBH1 could grow in KG and SH1 media containing dioxin, 2,4,5-T, pyrene and anthracene. After 7 days of inoculation, this strain degraded 72 % pyrene, 48.3% anthracene in KG medium and 63.3 % pyrene, 55.8 % anthracene in SH1 medium with 100 ppm initial concentration of each PAHs. This strain also showed ability in production of laccase in broth KG and SH1 media containing dioxin, 2,4,5-T, pyrene, anthracene. Laccase production by XKBH1 strain on KG medium was higher than in SH1 medium with activity was 2.7 U/lcontaining pyrene. This strain also produced laccase, LiP and MnP in SH1 medium with dioxin and 2,4,5-T as inducers. The highest MnP activity was 15.7 U/l in SH1 medium containing 2,4,5-T. Laccase activity measured at pH 3 increased approximative 74 fold incomparision to pH 5. Almost inducers enhancing laccase activity of XKBH1 strain and showed highest laccase activity (1073 U/l) in KG medium containing Veratryl Alcohol with initial concentration of 0.5 mM.