Evaluation of Different Standard Amino Acids to Enhance the Biomass, Lipid, Fatty Acid, and γ-Linolenic Acid Production in Rhizomucor pusillus and Mucor circinelloides

Abstract

In this study, 18 standard amino acids were tested as a single nitrogen source on biomass, total lipid, total fatty acid (TFA) production, and yield of γ-linolenic acid (GLA) in Rhizomucor pusillus AUMC 11616.A and Mucor circinelloides AUMC 6696.A isolated from unusual habitats. Grown for 4 days at 28°C, shaking at 150 rpm, the maximum fungal biomass for AUMC 6696.A was 14.6 ± 0.2 g/L with arginine and 13.68 ± 0.1 g/L with asparagine, when these amino acids were used as single nitrogen sources, while AUMC 11616.A maximum biomass was 10.73 ± 0.8 g/L with glycine and 9.44 ± 0.6 g/L with valine. These were significantly higher than the ammonium nitrate control (p < 0.05). The highest levels of TFA were achieved with glycine for AUMC 11616.A, 26.2 ± 0.8% w/w of cell dry weight, and glutamic acid for AUMC 6696.A, 23.1 ± 1.3%. The highest GLA yield was seen with proline for AUMC 11616.A, 13.4 ± 0.6% w/w of TFA, and tryptophan for AUMC 6696.A, 12.8 ± 0.3%, which were 38% and 25% higher than the ammonium tartrate control. The effects of environmental factors such as temperature, pH, fermentation time, and agitation speed on biomass, total lipids, TFA, and GLA concentration of the target strains have also been investigated. Our results demonstrated that nitrogen assimilation through amino acid metabolism, as well as the use of glucose as a carbon source and abiotic factors, are integral to increasing the oleaginicity of tested strains. Few studies have addressed the role of amino acids in fermentation media, and this study sheds light on R. pusillus and M. circinelloides as promising candidates for the potential applications of amino acids as nitrogen sources in the production of lipids.

Biologically active secondary metabolites from white-rot fungi

“…Furthermore, until 2019, approximately 35% of the naturally derived products approved by the US Food and Drug Administration (FDA) contributed to the development of pharmaceuticals ( Shankar and Sharma, 2022 ). Moreover, fungi are also able to synthesize various biologically active compounds such as pigments, dyes, antioxidants, nutraceuticals, dietary supplements, polysaccharides, and industrial enzymes ( Al-Mousa et al, 2022a ; Al-Mousa et al, 2022b ; Hassane et al, 2022 ; Mohamed et al, 2022 ). These fungal products are not only crucial for functional food and nutrition but also serve as important sources of pharmacological/medicinal substances ( Keller, et al, 2005 ; Hoeksma et al, 2019 ; Fukushima-Sakuno, 2020 ; Elhusseiny et al, 2021 ; Bhambri et al, 2022 ; Krupodorova et al, 2022 ).…”