Studies on agarolytic bacterial isolates from agricultural and industrial soil

BACKGROUND AND OBJECTIVES: Soil is rich in microbes which can be used for a variety of purposes starting from decomposition to antibiotic production. Agar-agar, extracted from the marine environment, is an important polysaccharide that has multiple uses after degradation by microbes. The aim of this study was to isolate bacteria that produced agarase enzyme, from a variety of soil sources and study their morphological and biochemical characterization. The enzyme activity of the isolates was also studied at 3 different pH, temperature and agar concentration. MATERIALS AND METHODS: Agarolytic isolates, were identified from industrial and agar- enriched agriculture soil by serial dilution method using MSA media that contains agar as the only source of carbon. Qualitative analysis of the isolates was determined by iodine assay while for quantitative analysis of enzyme activity, at standard and variable conditions, DNSA method was used. Genus of SELA 4 was identified. RESULTS: 4 isolates were obtained from industrial soil and 6 were obtained from agriculture soil enriched with laboratory agar. Isolate ‘SELA 4’ showed maximum relative activity (OD 0.92) followed by ‘CCIL 2 (OD 0.91) under standard culture conditions. Isolate ‘SELA 1’ showed maximum activity between 37°C–40°C, pH 5–7 with 1.5% agar concentration. “CGIPL 1” showed maximum activity at pH 9 while “SELA 2” and “SELA 4” showed maximum activity at pH 5. SELA 4 belonged to genus Microbacterium (Accession no. MG203882.1). CONCLUSION: The results showed that agar degrading bacteria can also be isolated from soil sources other than the usual marine sources and can be used for the industrial production of agarase enzyme.