Due to the actual emphasis in revalorization of agro-industrial wastes and cost reduction of enzymes production, this work aimed the optimization of lipase production from different oil cakes (OCs) produced in Brazil, by solid-state fermentation using Aspergillus ibericus MUM 03.49 and the application of the produced lipase in hydrolysis and esterification reactions. Higher lipase production was obtained using palm kernel oil cake (PKOC), yielding 127 ± 17 U/g of lipase (per mass of dry substrate). Through SSF optimization, using PKOC mixed with sesame oil cake (SOC) in a ratio of 0.45 g of PKOC per g total substrate at 57% moisture content (MC), a production of 460 ± 38 U/g of lipase was obtained after 6 days of fermentation. The obtained lipase was used in hydrolysis reactions, where it was observed higher production in short-chain triacylglycerols (TAGs) substrates. Also, it was applied in esterification reactions, where the formation of butyl decanoate using 5% (w/v) of biocatalyst was the most efficient. SSF of PKOC and SOC is a low cost competitive process to obtain A. ibericus lipase that can be used in aroma esters production, with application in the food industry.

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This study aimed to evaluate the use of a lyophilized fermented solid (named solid enzymatic preparation, SEP), with lipase activity, as a low-cost biocatalyst for esterification reactions of fatty acids present in acid raw materials for biodiesel synthesis. The SEP was obtained by solid-state fermentation (SSF) of soybean bran using the strain of Yarrowia lipolytica IMUFRJ 50682 and contains the lipases secreted by this yeast. The esterification reaction of ethanol and the predominant fatty acids present in different acid oil sources for biodiesel production (oleic, linoleic, stearic and palmitic acids) was investigated. Oleic acid conversion of above 85% was obtained after 24 h, using 30 wt% of SEP and ethanol/oleic acid molar ratio of 1, at 30 °C, in a reaction medium with and without solvent (n-hexane). Similar results were achieved with stearic (79%), palmitic (82%) and linoleic (90%) acids. The reusability of SEP was investigated over ten successive batches by washing it with different solvents (ethanol, water or n-hexane) between the cycles of ethyl oleate synthesis. Washing with water allowed the SEP to be reused for six cycles maintaining over 80% of the conversion reached in the first cycle. These results show the potential of this biocatalyst to reduce the content of free fatty acids in acid oils for biodiesel synthesis with a potential to be applied in a broad plethora of raw materials.

The production of polyunsaturated fatty acids from fish oil, which is related to various health benefits including effects against cardiovascular diseases, antihypertensive, anticancer, antioxidant, antidepression, anti-aging, and anti-arthritis effects, among others, can be advantageously performed through the application of lipase. However, the high cost associated with enzyme production can make the process unfeasible and thus alternative substrates should be investigated to solve these problems. This research aimed to produce lipase by Yarrowia lipolytica IMUFRJ50682 in solid-state fermentation using by-products of the food processing industry (andiroba oil cake and soybean meal) and verify the potential application in the initial hydrolysis of fish oil to further produce polyunsaturated fatty acids in a suitable process. A screening was carried out for the analysis of andiroba oil cake and soybean meal combinations in different proportions (0:100 to 100:0, respectively) at 48 h of the fermentation process. Afterward, the solid matrix composed by soybean meal and andiroba oil cake was supplemented with soy oil and Tween 80 to improve the lipase activity. The enzymatic extract was characterized in relation to the protein profile by electrophoresis. Finally, the enzymatic extract and the solid biocatalyst produced were applied to evaluate the potential hydrolysis of the fish oil in an initial study. Maximum lipolytic activity (63.7 U·g−1) was achieved using andiroba oil cake and soybean meal (50:50) after 24 h of fermentation. Soybean oil 1.5% and Tween 80 (0.001%) in an emulsion provided an increase of 1.5-fold (82.52 U·g−1) in the enzyme activity. The electrophoretic analysis demonstrated a band between 37 and 40 kDa that may be related to lipase and a band of 75 kDa referring to the α subunit of the β-conglycinin present in soybean meal. After 48 h, the solid biocatalyst showed a higher degree of hydrolysis (DH) (71.0%) than the enzymatic extract (61.5%). The solid biocatalyst was stable during storage at room temperature for 7 months. The production of lipases using Amazon fruit by-product and soybean meal in solid-state fermentation is viable as well as the application of the extract and solid biocatalyst in the initial application for the hydrolysis of fish oil to further produce polyunsaturated fatty acids in an industrially suited process.