Abstract

COMPARATIVE STUDY: DIFFERENT RECOVERY TECHNIQUES OF BIOSURFACTANT PRODUCED FROM PICHIA FERMENTANS ISOLATED FROM FERMENTED DAIRY WHEY WASTE

Jolly Mariam Johny*, P. Saravanakumari

ABSTRACT

Microbial surfactants are amphiphilic surface active molecules produced by bacteria, yeast, and fungi, which can reduce surface and interfacial tension between two immiscible fluid phases. In this study, a total of fifty yeast strains isolated from 8 fermented dairy whey waste samples, screened for biosurfactant activity, and cultured by enriching carbon and nitrogen sources. Among 6 yeast isolates having biosurfactant activity, DF-2 yeast strain exhibited the highest activity. Biochemical analysis and molecular characterization with 18S rRNA gene sequence indicates that DF-2 isolate belongs to Pichia species and closely related to Pichia fermentans. The yeast strain DF-2 exhibited a positive activity for drop collapse technique and microplate assay with an oil clearance diameter of 12 mm, with measured emulsification index 83.92 with a height of emulsion 23.6 cm after 120 hours. Optimization of carbon, nitrogen sources, and pH concentration for biosurfactant production by DF-2 isolate was performed and optimal condition for the biosurfactant production from Pichia fermentans was 4% soybean oil, 0.4% NaNO3 at pH 5.5 , 300C for 7 days. This paper provides an overview of the economical recovery techniques used to minimize the production cost of biosurfactants. Following gravity separation, three recovery methods include Acid precipitation, Ethyl acetate precipitation, and Acetone precipitation was performed. Recovery using acetone was found to be the best technique in this study, giving the highest oil clearance of 45mm and dried product per liter is 6.24g. The communication looks at the future perspective of biosurfactant production and its application in the healthcare and pharmaceutical sector.

Keywords: Microbial surfactants, 18S rRNA, Pichia fermentans, Recovery methods, Preliminary screening methods.