Erkki Pessa

Bio: Erkki Pessa is an academic researcher. The author has contributed to research in topics: Pectinase & Aspergillus niger. The author has an hindex of 1, co-authored 1 publications receiving 103 citations.

Screening of bacterial strains for pectinolytic activity: characterization of the polygalacturonase produced by Bacillus sp

Abstract: One hundred sixty eight bacterial strains, isolated from soil and samples of vegetablein decomposition, were screened for the use of citrus pectin as the sole carbon source.102 were positive for pectinase depolymerization in assay plates as evidenced by clearhydrolization halos. Among them, 30% presented considerable pectinolytic activity.The cultivation of these strains by submerged and semi-solid fermentation forpolygalacturonase production indicated that five strains of Bacillus sp produced highquantities of the enzyme. The physico-chemical characteristics, such as optimum pHof 6.0 Œ 7.0, optimum temperatures between 45 o C and 55”C, stability at temperaturesabove 40”C and in neutral and alkaline pH, were determined.Key words: Bacillus sp, polygalacturonase, pectinolytic activityINTRODUCTIONMany plant-pathogenic bacteria and fungi areknown to produce pectolytic enzymes useful forinvading host tissues. Moreover, theses enzymes areessential in the decay of dead plant material bynonpathogenic microorganisms and thus assist inrecycling carbon compounds in the biosphere (2).Pectinases include depolymerizing anddemethoxylating enzymes. Depolymerizing enzymesare polygalacturonase (EC 3.2.1), which cleaves theα-1,4 glycosidic bonds between two galacturonicacid residues, and pectin-lyase (EC 4.2.2), whichcatalyses a β-elimination reaction between twomethylated residues (3). De-esterifying enzymesinclude pectin-esterase (EC 3.1.1), which catalysesthe demethoxylation of methylated pectin,producing methanol and pectin (20).Preparations containing pectin-degradingenzymes have been extensively used to improve thestability of fruit and vegetable nectars and in theclarification of fruit juices and wines (5, 13, 21, 23,24). Currently, they are widely used in industry forretting of natural fibers and extraction of oils fromvegetable and citrus peels (4, 6).The enzymes preparations used in the foodindustry are of fungal origin because fungi are potentproducers of pectic enzymes and the optimal pH offungal enzymes is very close to the pH of many fruitjuices, which range from pH 3,0 to 5,5 (26). Suchpreparations are not suited for production ofvegetable purOes or other preparations in which pH

Effect of enzyme-aided pressing on anthocyanin yield and profiles in bilberry and blackcurrant juices

Abstract: Bilberries (Vaccinium myrtillus) and blackcurrants (Ribes nigrum) were treated with extensive dosages of commercial cell wall degrading enzyme preparations, i.e. Econase CE, Pectinex Ultra SP-L, Pectinex Smash, Pectinex BE 3-L and Biopectinase CCM. The enzymes were dosed based on the polygalacturonase activity. The juice yield was improved in both berries as a result of the enzymatic treatment. The improvement was more pronounced with blackcurrants owing to their thicker cell walls. The impact of the enzymatic treatment on anthocyanins present in the juices was investigated using HPLC-DAD. The enzyme preparations affected the contents and composition of anthocyanins in the juices. Pectinex Ultra SP-L, Pectinex Smash, Pectinex BE 3-L and Biopectinase CCM increased the total content of anthocyanins by 13-41% in the bilberry juices and by 18-29% in the blackcurrant juices. Econase CE, however, produced a dramatic decrease in the total anthocyanin content in the bilberry juice due to its enzyme profile, whereas no such effect was observed with the blackcurrant juice. All the enzyme mixtures tested produced a total or extensive loss of anthocyanidin galactosides in bilberry juice. Commercial enzyme preparations used in the production of berry juices can improve extraction of anthocyanins into the juice. However, they may effectively hydrolyse certain glycosides and thus affect the profile of extracted anthocyanins.  2005 Society of Chemical Industry

Production of pectolytic enzymes – a review

Abstract: Pectolytic enzymes play an important role in food processing industries and alcoholic beverage industries. These enzymes degrade pectin and reduce the viscosity of the solution so that it can be handled easily. These enzymes are mainly synthesized by plants and microorganisms. Aspergillus niger is used for industrial production of pectolytic enzymes. This fungus produces polygalacturonase, polymethylgalacturonase and pectinlyase. This review mainly concerns with the production of pectolytic enzymes using different carbon sources. It also deals with the effect of operating parameters such as temperature, aeration rate, agitation and type of fermentation on the production of these enzymes.