Abstract

SCREENING AND ISOLATION OF EPS PRODUCING MARINE BACTERIA AND OPTIMIZATION OF EPS PRODUCTION

Ayona Jayadev*, Lekshmi M. and Mary Franceena

ABSTRACT

The work was intended to screen and isolate EPS secreting bacterial strains from marine water samples. A total of twelve bacterial strains were isolated from collected water samples. These strains were screened for the secretion of EPS. Five bacterial strains showed EPS production. The effect of temperature, pH and incubation time on EPS production was identified for both protein content of EPS as well as carbohydrate content of EPS. EPS production was optimized under two different environmental condition i.e., pH (acidic neutral and alkaline (4, 7and 9) and temperature (20°C and 50°C) and at three different incubation times (24 hr, 72 hr and 120 hours). Quantification of protein was done by standard Lowry’s method. The production of EPS with respect to protein content was optimized in different temperature, pH and duration of incubation. All the strains produced proteins in EPS at highest quantities at 20°C and acidic as well as alkaline pH resulted in high protein content in EPS. Tb3 showed a sharp increase in the secretion of proteins in the EPS at 120 hours. Both at high temperature as well as at low temperature, the carbohydrate content was higher. Of all the strains, strain Tb1 was found to produce high amount of carbohydrate. Alkaline pH was found to be optimum for the heightened production of carbohydrate in EPS. In the case of effect of period of incubation the carbohydrate content increased from 24 hr to 72 hours. In strain Tb3 alone carbohydrate content of EPS increased considerably as incubation period increased. The protein content of this strain also showed a similar pattern.

Keywords: Exopolysaccharides, EPS, optimization, temperature, pH, Incubation period.