Oleaginous yeast could support oil, lipase production

According to research published in Acta Scientiarum Polonorum Technologia Alimentaria (DOI: http://dx.doi.org/10.17306/J.AFS.2021.0856), Candida viswanathii CCR8137 can produce lipase enzyme simultaneously to amass high concentrations of intracellular lipids. 

Lipases are key enzymes within a range of industries for their catalysing function of breaking down lipids into fatty acids and glycerol molecules. Further, as noted in the paper’s introduction, “Yeasts are industrial lipase producers due to their broad substrate specificity, selectivity and stability, and constitute the most important group of biocatalysts for biotechnological applications.” In this study, researchers from Brazilian universities and the Brazilian Agricultural Research corporation—EMBRAPA—analysed the Candida viswanathii CCR8137 yeast strain for its effects on glucose on lipid accumulation and lipase production drown in carbon sources: tributyrin, triolein, olive oil, sunflower oil and linseed oil. They also accessed its unsaturated fatty acids profile.

Results showed that vegetable oils or triolein as carbon sources led to enhanced enzyme and biomass yields compared to tributyrin. Researchers found tributyrin damaging for microbial growth, lipid accumulation and lipase production. Triolein (44.5% of the total biomass w/w) and olive oil (39.0% w/w) had the highest lipid accumulation, respectively. Further, olive oil had the best lipase production of 26,800 U/L; triolein's, sunflower's, and linseed oil’s lipase production values were 26,400 U/L, 21,900 U/L and 18,800 U/L, respectively. Researchers found tributyrin to inhibit lipase production. They noted, “C. viswanathii strain has been demonstrated to be a versatile alternative to biotechnological processes… The fermentation parameters analysed in this study also demonstrated the direct influence of fatty acid composition in vegetable oils on enzyme production and lipid accumulation.”

When analysing the effects nitrogen sources had on single cell oil and catalyst formation, researchers found the addition of organic nitrogen (yeast extract) led to an increased lipase production with olive oil and triolein— 26,800.0 U/L and 23,600.0 U/L, respectively.

Researchers experimented with glucose as the only carbon source and glucose added to olive oil when analysing the effects glucose had on lipid accumulation and lipase production. They found glucose alone decreased the levels of lipid accumulation and lipase production. However, glucose plus olive oil increased lipid accumulation and lipase production. Further, oleic acid was the primary fatty acid in lipid composition, followed by linoleic acid—not found in the cultivations with olive oil as the only carbon source. The fatty acid profile's major component was oleic acid, palmitic acid, and stearic acid, respectively.

Researchers concluded, “Co-production of lipase and microbial lipid by C. viswanathii CCR8137 can be part of a fundamental industrial bioprocess which may offer prominent cost-effective food products of a high nutritional grade. The high levels of lipase production and lipid accumulation observed in this study highlight that C. viswanathii CCR8137 has several promising industrial applications. The fatty acid profile obtained from yeast cultivations exhibited a single cell oil rich in omega-9 family fatty acids, and the addition of glucose to the culture medium resulted in omega-3 and omega-6 family constituents, which are attractive molecules for nutraceuticals and dietary supplements.”