Extracellular lipase production by Yarrowia lipolytica under magnetic fields.

This study aimed at estimating cultivation conditions to enable Yarrowia lipolytica NNRL Y-1095 to produce extracellular lipase and at evaluating the influence of magnetic fields (MF) on the lipase production and on its catalytic conditions. Culture conditions of carbon sources and surfactant defined to produce extracellular lipase were 10 g L-1 glucose, 15 g L-1 olive oil and 2 g L-1 Triton X-100. The highest lipase activity (34.8 U mL-1) was reached after 144 h when MFs were applied from 72 to 144 h of culture. It corresponds to an increase of 287.5% by comparison with the highest lipase activity in the control culture. MF application from 72 to 144 h did not change the optimal temperature of lipase, which was 37 °C, by comparison with the control. However, the optimal pH of the control was 7.0 while the one of lipase produced with MF was 8.0. Findings highlighted that the presence of MFs led to increase in synthesis of lipase by Y. lipolytica, with changes in the catalytic profile. This is one of the first studies of MF application to Y. lipolytica NRRL Y-1095 cultures to produce lipase.

Enzymatic biodiesel synthesis from yeast oil using immobilized recombinant Rhizopus oryzae lipase.

The recombinant Rhizopus oryzae lipase (1-3 positional selective), immobilized on Relizyme OD403, has been applied to the production of biodiesel using single cell oil from Candida sp. LEB-M3 growing on glycerol from biodiesel process. The composition of microbial oil is quite similar in terms of saponifiable lipids than olive oil, although with a higher amount of saturated fatty acids. The reaction was carried out in a solvent system, and n-hexane showed the best performance in terms of yield and easy recovery. The strategy selected for acyl acceptor addition was a stepwise methanol addition using crude and neutralized single cell oil, olive oil and oleic acid as substrates. A FAMEs yield of 40.6% was obtained with microbial oils lower than olive oil 54.3%. Finally in terms of stability, only a lost about 30% after 6 reutilizations were achieved.

Cultivation of Candida sp. LEB-M3 in glycerol: lipid accumulation and prediction of biodiesel quality parameters.

The quality of biodiesel from lipids produced by the yeast Candida sp. LEB-M3 was predicted, by the use of mathematical models for parameters that specify quality as a function of the fatty acid profile. The lipid production was studied according to the experimental design methodology, for different cultivation conditions for agitation and aeration. Lipid compositions were affected by the cultivation conditions, and the agitation presented a positive effect for the formation of monounsaturated fatty acids and negative effect for saturated fatty acids. Aeration had a positive effect on the formation of polyunsaturated fatty acids. According to the predictions by the mathematical models, the cetane number varied from 61 to 67, the oxidative stability from 11 to 17h, the iodine index from 55 to 75gI2/100g, density from 852 to 868kg/m(3). All cultivation conditions led to lipid compositions, whose predicted bioparameter values indicate that biodiesel from this lipid source should present current standard quality.

Exploration of Brazilian biodiversity and selection of a new oleaginous yeast strain cultivated in raw glycerol.

The objective of this study was to use glycerol generated from the synthesis of biodiesel to study the oleaginous potential of wild yeasts. An initial selection was performed via a rapid and qualitative technique by staining with Sudan Black B. Initially 129 yeasts were present, from which 5 were selected and cultivated in liquid medium containing pure or raw glycerol. The yeast LEB-M3, isolated from the Pantanal, presented lipid content of 20.46% and 56.58% for cultivation in pure and raw glycerol, respectively. This strain was genotypically identified as Candida sp. The fatty acid profile showed predominance of oleic acid (C18:1), 57.35% for cultivation in pure glycerol, and in raw glycerol linoleic acid (C18:2) was predominant (46.0%). It was possible to select a yeast with high lipid concentrations 9.14 g/L and fatty acid profile similar to vegetable oils commonly used in the synthesis of biodiesel.