Screening of indigenous microbiological resources for environmental remediation and classification of novel strains

Abstract

A large variety of indigenous microorganisms (polysaccharide-degrading bacteria, moderately halophilic bacteria degrading aromatic hydrocarbons, and aerobic bacteria degrading (chlorinated) aromatic compounds) for application in environmental remediation have been isolated and characterized. For the screening of polysaccharide-degrading bacteria, the direct plating method using insoluble chromogenic substrates has been used. Totally 63 strains degrading cellulose and/or xylan have been isolated. Phylogenetic analysis, based on 16S rRNA gene partial sequences, showed that isolated strains belonged to Actinobacteria (32 %, including the genera Arthrobacter, Cellulomonas, Cellulosimicrobium, Microbacterium and Streptomyces), Bacteroidetes (17 %, including the genera Chitinophaga, Chryseobacterium, Flavobacterium, Pedobacter and Runella), Firmicutes (40 %, including the genera Bacillus and Paenibacillus) and Proteobacteria (11 %, including the genera Cellvibrio, Pelomonas, Pseudomonas, Rhizobium and Roseateles). For the screening of moderately halophilic bacteria degrading aromatic hydrocarbons, the process of enrichment and subsequent isolation has been applied using saline samples from seashores and solar salterns in Anmyoendo. The enrichment method used in this study targeted bacteria degrading benzene, phenol or toluene, or more than two with 10 % of salinity. Denaturant gradient gel electrophoresis (DGGE) analysis and terminal restriction fragment length polymorphism (T-RFLP) analysis of polymerase chain reaction (PCR)-amplified DNA fragments prepared from extracted DNA were used to compare the composition of bacterial communities according to the spatial differences. Totally 70 strains have been isolated. Phylogenetic analysis, based on 16S rRNA gene partial sequences, showed that isolated strains belonged to Firmicutes (21 %, including the genera Halobacillus and Virgibacillus), α-Proteobacteria (6 %, including the genera Rhodovibrio, Roseivivax and Ro...