Optimization of Physical Parameters of Fermentation Medium for Biosynthesis of Alginate by a Vinelandii Using Molasses as ‘C’ Source

Abstract

Biopolymer have varied industrial applications. Alginate is one such polymer conventionally extracted from brown algae of marine waters having versatile applications. Due to its increased market demand alternative options are being investigated for its synthesis from microbes. The present study focuses on the optimization of various physical parameters at flask level. Fermentation medium consisted of pre-treated sugar cane molasses (2%) as carbon source and peptone as nitrogen source (0.5 g). The optimized parameters were found to be, temperature as 30oC, pH 7.0, incubation period 84 hours, agitation rate 150 rpm, inoculum age 36 hours and inoculum level 5%. Under optimized parameters the significant (P<0.05) alginate yield was found to be 5.71 g/L (PS) and 6.28 g/L (MS) with the corresponding dry cell mass (DM) as 6.28 g/L (PS) and 6.92 g/L (MS). The plate assay of the alginate lyase activity indicated that the improved strain has less activity (11 mm) as compared to the parent strain (14 mm). Alginate lyases influence the yield and the molecular weight of the product. Hence the zone of hydrolysis on the plates correlates with the maximum yield obtained. HPLC chromatogram indicated the peak of purified alginate with retention time of 3.332 minutes with purity of 81.22 %.