Lipase production by Aspergillus brasiliensis in solid-state cultivation of malt bagasse in different bioreactors configurations.

Paulo Eichler,Daniela C Bastiani,Marco A.Z Ayub,Fernando A Santos

doi:10.1590/0001-3765202020180856

Abstract

We evaluated the conditions to produce lipase in solid-state cultivation using a recently isolated strain of Aspergillus brasiliensis 157f in bioreactors of different configurations: static flat-bed, plugged-flow bed with forced water-saturated aeration, and pilot-scale rotating drum bioreactor, using malt bagasse as substrate. Lipase production was optimized applying experimental design analysis, which showed optima parameters defined as pH 7.7, addition of 11.3 % of soybean oil to the medium, and culture temperature of 32.7 oC, in static flat-bed. The highest enzyme activity (9.8 U.g-1 substrate) was obtained in the plugged-flow bed with forced water-saturated aeration. The fermented culture medium was lyophilized to create a solid enzymatic preparation (SEP), which was used to test the possibility of using this cheap biocatalyst in bioreactors to mediate esterification and transesterification reactions. SEP presented lipase activities of 7.35 U.g-1 substrate, indicating the possibility of further enhancing aspects of the use of such biocatalyst.

Highlights

IntroductionLipases (triacylglycerol hydrolases, EC 3.1.1.3), are enzymes that catalyze the hydrolysis of triglycerides, producing free fatty acids and glycerol
Lipases, are enzymes that catalyze the hydrolysis of triglycerides, producing free fatty acids and glycerol
Is estimated an annual production of two billion hectoliters of beer worldwide, with China being the largest producer, followed by USA and Brazil (Kirin 2017), representing a potential of forty million tons of spent malt available that could be used in biorefinery processes every year, at low or no cost (Aliyu & Bala 2013). Considering these aspects, the objective of this study was to evaluate optimal conditions for lipase production using a new strain of Aspergillus brasiliensis 157f, isolated by our group, growing under solid-state cultivation using spent malt bagasse

Summary

Introduction

Lipases (triacylglycerol hydrolases, EC 3.1.1.3), are enzymes that catalyze the hydrolysis of triglycerides, producing free fatty acids and glycerol They can catalyze alcoholysis, esterification, and transesterification of fatty acids (Treichel et al 2010). Based on their versatility, selectivity, moderate reaction conditions, and susceptibility to immobilization, lipases are extremely interesting from a commercial point of view. Selectivity, moderate reaction conditions, and susceptibility to immobilization, lipases are extremely interesting from a commercial point of view These enzymes are used in various industrial processes such as the production of foods, pharmaceuticals, cosmetics, detergents, and biofuels, among other uses (Treichel et al 2010, Choudhury & Bhunia 2015, Gupta et al 2015). The enzymatic route generates pure glycerol as by-product and biodiesel of better quality compared to chemical synthesis, and the possibility of using ethanol, milder reaction conditions, and no need to neutralize the final product (De Castro et al 2012)

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