Growth optimization and natural products of Geotrichum candidum isolated from the Mediterranean Sea, Egypt

Abstract

: In this study, a total of 28 Geotrichum candidum isolates were identified from the Mediterranean Sea coast and Edku Lake. Among these, one isolate, G. candidum (SUMCC 23002), was selected for further investigation to assess its potential for biomass and bioactive compounds production. Different low-cost carbon sources were evaluated for biomass production compared to glucose. Crude extracts were tested against pathogenic microbes Bacillus subtilis, Escherichia coli, Candida albicans, and Aspergillus fumigatus. Among the tested carbon sources, sugarcane hydrolysate was the most biomass productive (10.37 g/L), followed by dates’ juice (8.34 g/L). Notably, only crude extract of glucose culture showed promising antibacterial activity against Bacillus subtilis. Active crude extract was fractionated and nine bioactive chemical compounds were identified using GC-MS, of which six compounds are known for their antibacterial activity namely: Cis-13-octadecenoic acid (with a total area of 40.71%), 9-Octadecenoic acid (Z)-, 2-hydroxy-1-(hydroxymethyl) ethyl ester (15.07%), n-Hexadecanoic acid (12.09%), 9(Z)-Octadecenoic acid (9.34%), Cis-vaccenic acid (8.06%), and 9,12-Octadecadienoic acid (Z,Z)- (1.27%).