Agroindustrial byproduct-based media in the production of microbial oil rich in oleic acid and carotenoids.

This study focuses on the potential of Rhodotorula mucilaginosa CCT 7688 in simultaneous production of lipids and carotenoids in agroindustrial byproduct-based media and specially aims at establishing a process condition that guarantees high concentrations of both bioproducts, i.e., a carotenoid-rich microbial oil with potential economic value and health benefits attributed to carotenoids and fatty acids. Four different combinations of cultivation modes (batch and fed-batch) and alternative substrates (crude glycerol, sugarcane molasses and corn steep liquor) were tested. The M2-B assay, which comprises the use of an agroindustrial byproduct-based medium without any supplementation (70 g L-1 sugarcane molasses and 3.4 g L-1 corn steep liquor) and batch mode, was selected as the most promising one to produce both compounds. Total carotenoid production and total lipid content were 1794.2 µg L-1 and 43.2% (w/w), respectively, after 144 h of cultivation. The fatty acid profile showed predominance of oleic acid (69.9%) and palmitic acid (23.2%). Thus, R. mucilaginosa CCT 7688 may be used in simultaneous production of lipids and carotenoids successfully; its fatty acid profile is similar to that found in olive oil. Both compounds are economically interesting and have great possibility of future commercial applications.

Enzymatic synthesis optimization of isoamyl butyrate from fusel oil

Many food, cosmetic and pharmaceutical industries have increased their interest in short-chain esters due to their flavor properties. From the industrial standpoint, enzyme reactions are the most economical strategy to reach green products with neither toxicity nor damage to human health. Isoamyl butyrate (pear flavor) was synthesized by isoamyl alcohol (a byproduct of alcohol production) and butyric acid with the use of the immobilized lipase Lipozyme TL IM and hexane as solvents. Reaction variables (temperature, butyric acid concentration, isoamyl alcohol:butyric acid molar ratio and enzyme concentration) were investigated in ester conversion (%), concentration (mol L-1) and productivity (mmol ester g-1 mixture . h), by applying a sequential strategy of the Fractional Factorial Design (FFD) and the Central Composite Rotatable Design (CCRD). High isoamyl butyrate conversion of 95.8% was achieved at 24 hours. At 3 hours, the highest isoamyl butyrate concentration (1.64 mol L-1) and productivity (0.19 mmol ester g-1 mixture . h) were obtained under different reaction conditions. Due to high specificity and selectivity of lipases, process parameters of this study and their interaction with the Lipozyme TL IM are fundamental to understand and optimize the system so as to achieve maximum yield to scale up. Results show that fusel oil may be recycled by the green chemistry process proposed by this study.

Biosurfactant production by Phialemonium sp. using agroindustrial wastes: influence of culture conditions

Biosurfactant are surface active compounds with emulsifying capacity and are produced by microorganisms, and they may be affected by factors related to microbial cultivation, such as pH, salinity, incubation time, carbon and nitrogen sources. The aim of this work was to study the influence of the culture conditions on the production of biosurfactants by Phialemonium sp using agroindustrial wastes. The processing parameters of temperature, humidity and pH produced the most significant effects on the production of biosurfactant and emulsifying activity. The maximum concentration of biosurfactant obtained in this study was equivalent to a surface tension reduction of 8.5 mg L-1 surfactin commercial solution using wheat bran, pH of 4.5, and 0.5% of soybean oil added at 30°C. Under these conditions, 83.4 EU g-1 of emulsifying activity, 16.4 g L-1 of emulsifier index and 18.3 U g-1 lipolytic capacity were obtained.

Evaluation of the composition of culture medium for yeast biomass production using raw glycerol from biodiesel synthesis

The work herewith investigated the production of yeast biomass as a source of protein, using Yarrowia lipolytica NRRL YB-423 and raw glycerol from biodiesel synthesis as the main carbon source. A significant influence of glycerol concentration, initial pH and yeast extract concentration on biomass and protein content was observed according to the 2v5-1 fractional design. These factors were further evaluated using a central composite design and response surface methodology, and an empirical model for protein content was established and validated. The biomass of Yarrowia lipolytica NRRL YB-423 reached 19.5 ± 1.0 g/L in shaken flasks cultivation, with a protein content of 20.1 ± 0.6% (w/w).