Acid lipase from Candida viswanathii: production, biochemical properties, and potential application

Abstract

Influences of environmental variables and emulsifiers on lipase production of a Candida viswanathii strain were investigated. The highest lipase activity (101.1 U) was observed at 210 rpm, pH 6.0, and 27.5°C. Other fermentation parameters analyzed showed considerable rates of biomass yield (Y L/S = 1.381 g/g), lipase yield (Y L/S = 6.892 U/g), and biomass productivity (P X = 0.282 g/h). Addition of soybean lecithin increased lipase production in 1.45-fold, presenting lipase yield (Y L/S ) of 10.061 U/g. Crude lipase presented optimal activity at acid pH of 3.5, suggesting a new lipolytic enzyme for this genus and yeast in general. In addition, crude lipase presented high stability in acid conditions and temperature between 40 and 45°C, after 24 h of incubation in these temperatures. Lipase remained active in the presence of organic solvents maintaining above 80% activity in DMSO, methanol, acetonitrile, ethanol, acetone, 1-propanol, isopropanol, and 2-propanol. Effectiveness for the hydrolysis of a wide range of natural triglycerides suggests that this new acid lipase has high potential application in the oleochemical and food industries for hydrolysis and/or modification of triacylglycerols to improve the nutritional properties.

Figure 1

Effect of the agitation speeds in orbital shake on lipase production (a), specific activity (b), and Candida viswanathii growth (c). Culture conditions: liquid cultures were carried out in Vogel's medium with 1.5% (w/v) olive oil and 0.2% (w/v) yeast extract, at pH 6.0 and 28°C. (■) 150 rpm; (⚫) 180 rpm; (▲) 210 rpm.

Figure 2

Effect of temperature on growth and lipase production by C. viswanathii. Culture conditions: cultures were carried out in Vogel's medium with 1.5% (w/v) olive oil and 0.2% (w/v) yeast extract and agitated at 210 rpm, at pH 6.0. (■) lipase activity, (□) specific activity, and (⚫) biomass.

Figure 3

Optimal pH (a) and pH stability (b) of the crude C. viswanathii lipase. Assay conditions: 0.05 M glycine-HCl buffer from 2.0 to 3.0, McIlvaine buffer from 3.0 to 8.0, and 0.05 M glycine-NaOH from 8.0 to 10. Lipase activity assays were carried out at 37°C (a) and in McIlvaine buffer pH 3.5, at 37°C (b).

Figure 4

Optimal temperature (a) and thermal stability (b) of the crude C. viswanathii lipase. Assay conditions: McIlvaine buffer pH 3.5 (a). The enzymatic preparation was incubated at (■) 40, (⚫) 45, and (▲) 50°C, without substrate. The residual lipase activity was assayed with McIlvaine buffer, pH 3.5, at 40°C (b).

Figure 5

Hydrolysis of triacylglycerols by crude Candida viswanathii lipase. Assay conditions: triacylglycerols hydrolysis was carried out in McIlvaine buffer pH 4.0 with 5% (w/v) Triton X-100 and hydrolysis activities were assayed by titration method.