Screening of biosurfactant producing yeasts isolated from mangrove ecosystem of Surat region of Gujarat, India

Abstract

Background/ Objectives: Biosurfactants are extracellular surface-active compounds produced by bacteria, fungi and yeast. Interest in biosurfactant has been increasing due to their unique properties. The objective of this study is to screen for potential biosurfactant producing yeasts from mangrove areas of Gujarat in India. Methodology: The biosurfactant producing yeasts isolated from five different mangrove sites i.e. Hazira, Mandroi, Mirzapur, Kantiyajal and Machhad of Surat, Gujarat during summer season of 2015. Isolated yeasts were screened for the production of biosurfactant by Parafilm M, Oil displacement and Emulsification index method in which cottonseed oil was used as a substrate. The type of biosurfactant produced was identified by Phenol-sulfuric acid test, Biuret test and phosphate test. Findings: Total twenty four yeasts were isolated from soils of sampling sites. Yeasts were initially screened by Parafilm M and oil displacement method. Out of these 24 isolate, 6 isolates namely, Ky-48, Ky-53, Ky-54, Ky-84, Ky-86 and Ky-87 showed promising biosurfactant activity. These six isolates were further subjected to secondary screening method: Emulsification test, to identify biosurfactant production. Two isolates, namely Ky-46 (emulsification index: 61.53 %) and Ky-86 (emulsification index: 46.66 %) showed maximum biosurfactant production. All six isolates showed positive result for phenol- sulfuric acid method. This indicated that the isolated biosurfactant was Glycolipid in nature. Novelty/Applications: Few mangrove yeasts have potential to produce high amount of glycolipid that can be used in food processing and detergents, healthcare and cosmetics industries. Keywords: Biosurfactant; emulsification index; oil displacement; glycolipid