Pectin Lyase Activity in a Penicillium italicum Strain

Abstract

An extracellular pectin lyase (PNL) [poly-(methoxygalacturonide)lyase; EC 4.2.2.10] produced by Penicillium italicum CECT 2294 grown on a surface bran (natural medium) or in a submerged (synthetic medium) culture was investigated. Both culture filtrates showed macerating activity at low pH on cucumber, potato, and orange tissues. The physicochemical properties of the enzyme obtained from both culture methods were identical, as well as its catalytic properties, which were assayed by different methods. The molecular mass of the PNL obtained by gel filtration chromatography was 22 kDa; the isoelectric point was 8.6, as determined by chromatofocusing; and the enzyme was able to catalyze the eliminative cleavage of pectins with low (37%) and high (from 54 to 82%) degrees of esterification. The PNL produced in liquid medium showed a K,m for pectin (degree of esterification, 70%) of 3.2 mg/ml, and the optimum pH was 6.0 to 7.0. This enzyme was stable at 50°C and at pH 8.0. The ability of this PNL to macerate plant tissues in acidic environmental conditions, its stability at low pH and temperatures up to 50°C (thus preventing mesophilic microbial growth), and the absence of pectinesterase make this preparation useful for the food industry.

Enhanced polygalacturonase production by Aspergillus niger NRRL-364 grown on supplemented citrus pectin

“…Pectin lyase (PL: EC 4.2.2.2) activity was determined spectrophotometrically with a Hitachi U-2OOO spectrophotometer by monitoring the increase in the A,,, (Albersheim 1966;Alana et al 1990). The reaction mixture (1.25 ml) contained 0.1 mol I-' citratephosphate buffer (pH 6.0), 0.5% (w/v) citrus pectin (D.E.…”

Production of polygalacturonase by Aspergillus niger BC23 isolated from Irvingia gabonensis (African mango) fruit

“…The authors reported slight inhibition of PG action in the presence of Zn 2+ and Ba 2+ and that the enzyme activity was completely lost in the presence of Hg 2+ . Similarly Ca 2+ , Mg 2+ , Mn 2+ and Zn 2+ were reported to activate pectinase from Penicillin italicum, but it was inhibited by Cu 2+ and Fe 2+ [25]. Mg 2+ and Zn 2+ stimulated pectinase activity by 115 and 138% respectively as compared to native enzyme activity [26].…”

“…The effect of temperature on enzyme activity was studied by incubating 1mL of the enzyme solution contained in test tube and 1 mL of 1% citrus pectin solution prepared in 2 mL of 0.2 M potassium phosphate buffer (pH 5.6) for 2 h at various temperatures (20,25,30,35,40,45, 50, 55 and 60 °C) in a thermo static water bath (Kottermann, Bremen, Germany). The reaction was stopped by the addition of 2 mL DNS reagent and the enzyme activities were determined.…”

Production of pectin lyase by Penicillium griseoroseum in bioreactors in the absence of inducer

“…Among the pectinases, pectin lyase (PL) is of particular interest because it acts directly on pectin without the need for previous action by other enzymes of the pectinolytic complex (1). Degumming of ramie fibers with PL of Penicillium griseoroseum produces fibers with quality superior to those produced by a commercial enzyme complex because P. griseoroseum does not produce cellulolytic enzymes (10).…”

“…Among the filamentous fungi, some of the genus Penicillium are good producers of PL (1). Penicillium griseoroseum produces PL when grown in a medium containing pectin (10), its natural inducer.…”