Experimental design applied to the optimization and partial characterization of pectin-methyl-esterase from a newly isolated Penicillium brasilianum

摘要

The objective of this work was to optimize the medium composition for maximum pectin-methyl-esterase (PME) production from a newly isolated strain of?Penicillium brasilianum?by submerged fermentation.?A Plackett-Burman design was first used for the screening of most important factors, followed by a 23?full experimental design, to maximize?the enzyme production.?The maximum?pectin-methyl-esterase?activity was4.0?U/mL at 24?h of bioproduction using a pectin concentration of 32.0 g/L, yeast extract of 30.0 g/L, potassium phosphate of 8.0 g/L, iron (II) sulfate of 0.02 g/L, at 30°C, stirring rate of 180 rpm and initial pH of 5.5. The kinetic evaluation showed that after 27?h of fermentation, a consumption of 15% of total organic carbon and 10% of nitrogen was observed. The crude enzymatic extract kept about 80% of its initial activity after 1848 h under low temperatures. An increase of PME activity was observed after incubation at high temperatures. The residual activity of the extracts after 1728 h of incubation was about 95% for all tested pH values (5, 7, 9 and 11). The application of 0.5% (v/v) of PME crude extract for clarification of peach juice showed a reduction on the viscosity (7.20%) and turbidity (14.11%).