Yeast Diversity in the Mangrove Sediments of North Kerala, India

Objective: Mangrove sediments, due to their unique environment, are considered to be a crucial habitat in identifying yeast strains with potent industrial, biotechnological and bioremediation properties. The goal of the current study was to understand the presence, diversity and hydrolytic enzyme properties of yeasts from the mangrove sediments of North Kerala. Materials and Methods: Sampling was done during the period 2018-2020 from mangrove sediments of 5 districts along the North Kerala coast. Isolation of yeast was done on yeast glucose peptone agar, and isolates were tested for their potential for the production of extracellular enzymes viz. amylase, cellulase, chitinase, DNase, lipase, ligninase, pectinase, protease and urease, using standard media with specific substrates. Morphological assessment, biochemical characterization and molecular identification of the isolates were performed. The phylogenetic tree of the selected yeast strains was constructed with the Maximum Likelihood method using MEGA X software. Results: A total of 482 yeast strains belonging to 12 genera were obtained from the mangrove sediment samples, the most dominant genera being Candida (56.3%). Kluveromyces, Debaromyces, Torulaspora, Trichosporon, pigmented yeast Rhodotorula, Cyberlindnera, Wickerhamiella, Pichia, Trichoderma, Meyerozyma and Kodamaea were the other genera identified. The majority of the yeast present in the mangrove sediment samples were lipolytic (68%), followed by ureolytic (23%), ligninolytic (16%), cellulolytic (9%), DNAlytic (9%), proteolytic (8%), amylolytic (6%), pectinolytic (4%) and chitinolytic (2%) forms. All 12 genera of yeast obtained had positive forms for extracellular lipase. Conclusion: The yeast strains obtained from mangrove sediments in the study were found to be ecologically important and have great biotechnological potential. Keywords: Yeast, mangrove sediments, hydrolytic enzymes, phylogeny, North Kerala