Optimization of the pigment production conditions and investigation of bio-active properties of newly isolated Talaromyces albobiverticillius genbank®pq616019.1 as a potential food colorant/food additive

Abstract

Talaromyces albobiverticillius, a group of fungi that synthesize pigment metabolite “Azaphilone” Generally Recognize as Safe, is an emerging organism due to its potential industrial applications. This study aimed to optimize pigment production conditions and investigate the bio-active properties of a soil-derived novel strain of T. albobiverticillius GenBank®PQ616019.1 isolated from Makandawa forest reserve, Sri Lanka as a potential food colorant. Prior to growth optimization, its mycotoxin synthesis ability was investigated using Liquid Chromatography Tandem Mass Spectrometry (LOD 0.8 µgkg-1). To optimize fermentation conditions, liquid culture flasks were tested with different concentrations of carbon sources (glucose, maltose, sucrose, lactose, dextrose, galactose and soluble starch), nitrogen sources (peptone water, yeast extract, ammonium nitrate and sodium nitrate), pH values (4, 5, 6), temperatures (22, 25, 27 oC), stirring/non- stirring conditions and fermentation times (0-240 hours). Antioxidant properties were evaluated using DPPH free radical scavenging and ferric-reducing antioxidant power assay. Antibacterial properties were evaluated using agar well diffusion method. Results revealed that T. albobiverticillius PQ616019.1 is non-aflatoxin synthesizing strain having optimum growth and pigment production in the presence of peptone water (Nitrogen source), at pH 5, at 25 oC with a fermentation time of 168 hours under non-stirrer conditions (significant atP < 0.05). Although non-significant (P > 0.05), growth and pigment production were optimal withlactose as the carbon source. The red-colored extracellular pigment exhibited strong ferric reducing activity (30.255 ± 0.105 mg Trolox Eq/g of dye) and moderate DPPH free radical scavenging activity (8.371 ± 0.365 mg Trolox Eq/g of dye). Antibacterial activity was observed against Escherichia coli ATCC8739 (9.96 ± 0.50 mm) and Bacillus subtilis ATCC6633 (10.84 ±0.71mm) at the concentration of 0.05 mg/µL. Further chemical characterization and structure elucidation of the metabolite are currently under investigation.