Production of arachidonic acid by Mortierella alpina using wastes from potato chips industry.

AIMS: This research aimed to determine the potential use of wastes from the potato chips industry as a carbon source to develop an economical culture medium for the production of biomass, lipids and arachidonic acid (ARA) by Mortierella alpina. METHODS AND RESULTS: A synthetic culture medium was optimized using a Plackett-Burman and central composite rotatable design, and used as a base to evaluate and characterize the potential use of wastes from the potato chips industry as carbon sources for the production of biomass, lipids and ARA by M. alpina. The waste was selected among other solid and liquid hydrolysed residues/by-products, and local low-cost alternatives for nitrogen sources were also evaluated. After 6 days of fermentation, the biomass concentration reached 20 g l-1 with 40% of total lipids, and a 35% ARA content in the lipids fraction. Savings in production were calculated using a sensitivity analysis for the alternative culture medium in different scenarios. CONCLUSIONS: This study showed a 7% savings in culture media expenses in the production of ARA-enriched biomass of M. alpina, compared to the conventional synthetic culture medium, when waste from the potato chips industry was used as an alternative source of carbon and macro/microelements, supplemented with a low-cost yeast extract alternative. SIGNIFICANCE AND IMPACT OF THE STUDY: The demonstration of the use of potato chips wastes as a low-cost carbon source for the biomass, lipids and ARA production, suggesting an eco-friendly alternative for the use of agri-food wastes for valuable metabolites production.

Production, characterization, and biological activity of a chitin-like EPS produced by Mortierella alpina under submerged fermentation.

The production of a chitin-like exopolysaccharide (EPS) was optimized through experimental design methods, evaluating the influence of urea, phosphate, and glucose. Under optimized conditions, up to 1.51 g/L was produced and its physicochemical characteristics were evaluated by chromatography, NMR, and FTIR spectroscopy, and rheological techniques. The results showed a homogeneous EPS (Mw 4.9 × 105 g mol-1) composed of chitin, linear polymer of ß-(1→4)-linked N-acetyl-d-glucosamine residues. The acetylation degree as determined by 13C CP-MAS NMR spectroscopy was over 90 %. The EPS biological activities, such as antioxidant effect and antitumor properties, were evaluated. To the best of our knowledge, this is the first study on the production of a new alternative of extracellular chitin-like polysaccharide with promising bioactive properties from the filamentous fungus M. alpina.

Separation of microbial oil produced by Mortierella isabellina using polymeric membranes.

The objective of this work was to concentrate, through a membrane separation process, the fatty acids from oil/solvent mixture. The oil was obtained by ultrasound-assisted extraction from freeze-dried cells of Mortierella isabellina. The concentration of the fatty acids was investigated using flat-sheet polymer membranes of ultrafiltration and nanofiltration. The effects of temperature and pressure were evaluated by the retention of the fatty acids. Oil retentions between 45.23 and 58.20% to ultrafiltration membrane and 43.50 and 56.00% to nanofiltration membrane were observed. The best condition for the ultrafiltration membrane was 4 bar and 40 °C and for nanofiltration membrane was 12 bar and 50 °C. The oil contains a high concentration of oleic acid and palmitic acid that is a desirable property for the biodiesel production. The results showed the applicability of this technology in the solvent recovery step whereas the oil recovered contains a high concentration of fatty acids.

Expression analysis for genes involved in arachidonic acid biosynthesis in Mortierella alpina CBS 754.68.

The time courses for production of fungal biomass, lipid, phenolic and arachidonic acid (ARA) as well as expression of the genes involved in biosynthesis of ARA and lipid were examined in Mortierella alpina CBS 754.68. A significant increase in the arachidonic acid content in lipids that coincided with reduced levels of lipid was obtained. Reduced gene expression occurred presumably due to the steady reduction of carbon and nitrogen resources. However, these energy resources were inefficiently compensated by the breakdown of the accumulated lipids that in turn, induced up-regulated expression of the candidate genes. The results further indicated that the expression of the GLELO encoding gene is a rate-limiting step in the biosynthesis of ARA in the early growth phase.

Lipid profiling and corresponding biodiesel quality of Mortierella isabellina using different drying and extraction methods.

Four lipid extraction methods (Bligh & Dyer, hexane & isopropanol, dichloromethane & methanol, and hexane) were evaluated to extract lipid from freeze- and oven-dried fungus Mortierella isabellina ATCC42613. The highest lipid yield (41.8%) was obtained from Bligh & Dyer extraction on the oven-dried fungal biomass with a methanol:chloroform:water ratio of 2:1:0.8. Other lipid extraction methods on both freeze- and oven-dried samples had lipid yields ranging from 20.7% to 35.9%. Non-polar lipid was the main lipid class (more than 90% of total lipid) in M. isabellina. Regarding fatty acid profile, there was no significant difference on fatty acid concentration between different drying and extraction methods. Estimation of biodiesel fuel properties using correlative models further demonstrated that the fungal biodiesel is a good alternative to fossil diesel.

Expression analysis for genes involved in arachidonic acid biosynthesis in Mortierella alpina CBS 754.68

The time courses for production of fungal biomass, lipid, phenolic and arachidonic acid (ARA) as well as expression of the genes involved in biosynthesis of ARA and lipid were examined in Mortierella alpina CBS 754.68. A significant increase in the arachidonic acid content in lipids that coincided with reduced levels of lipid was obtained. Reduced gene expression occurred presumably due to the steady reduction of carbon and nitrogen resources. However, these energy resources were inefficiently compensated by the breakdown of the accumulated lipids that in turn, induced up-regulated expression of the candidate genes. The results further indicated that the expression of the GLELO encoding gene is a rate-limiting step in the biosynthesis of ARA in the early growth phase.

Expression analysis for genes involved in arachidonic acid biosynthesis in Mortierella alpina CBS 754.68

The time courses for production of fungal biomass, lipid, phenolic and arachidonic acid (ARA) as well as expression of the genes involved in biosynthesis of ARA and lipid were examined in Mortierella alpina CBS 754.68. A significant increase in the arachidonic acid content in lipids that coincided with reduced levels of lipid was obtained. Reduced gene expression occurred presumably due to the steady reduction of carbon and nitrogen resources. However, these energy resources were inefficiently compensated by the breakdown of the accumulated lipids that in turn, induced up-regulated expression of the candidate genes. The results further indicated that the expression of the GLELO encoding gene is a rate-limiting step in the biosynthesis of ARA in the early growth phase.

Synthesis and biotransformation of tetrahydroquinoline by Mortierella isabelina.

Tetrahydroquinoline (1), prepared by a traditional synthetic method, the imino Diels-Alder reaction, was biotransformed by Mortierella isabelina to afford a new compound, 2, characterized by spectroscopic methods.