Production of yeast polygalacturonase on dairy wastes

Production of pectic enzymes in yeasts

“…The influence of other parameters such as the pH of the medium, inoculum size, incubation time or the addition of nitrogen sources has received less attention. Murad and Foda [23] found that the highest value of enzymic activity can be obtained in a medium with an initial pH of 5.0, the inoculum size being circa 4% (v/v). The effect of the nitrogen source on the pectolytic activity was studied in only two cases.…”

“…The effect of the nitrogen source on the pectolytic activity was studied in only two cases. Murad and Foda [23] reported that in K. lactis the activity increased when the media were supplied with an organic nitrogen source such as yeast extract or peptone but that when an inorganic nitrogen source was added, the enzymic activity remained unaffected. In these studies, the cultures were usually grown for 3 days [12, 18, 23] and the pectolytic activity decreased with a longer period of culture.…”

Industrially Important Carbohydrate Degrading Enzymes from Yeasts: Pectinases, Chitinases, and β-1,3-Glucanases

“…It has been reported that highest pectolytic activities were obtained in media containing yeast extract by Debaryomyces nepalensis (Gummadi and Kumar, 2006b ). Similarly Murad and Foda ( 1992 ) found that the highest value of enzymatic activity when media contained yeast extract or peptone. The effect of medium components and various operating parameters such as pH, agitation and aeration has also been studied for maximum production of pectin lyase (PL) and pectate lyase (PGL) by D. nepalensis Kumar, 2006d , 2007 ).…”

“…Roelofsen reported certain yeasts belonging to the genera Candida, Pichia, Saccharomyces and Zygosaccharomyces have the ability to attack cell wall pectin, suggesting that the yeasts produced polygalacturonases (Roelofsen, 1953 ). Pectinases have also been reported in Kluyveromyces marxianus , K. fragilis (Schwan et al, 1997 ), K. lactis (Sakai et al, 1984 ) and Geotrichum lactis (Murad and Foda, 1992 ), which produces an endo-PG assumed to be important in the breakdown of the pectinaceous layer surrounding coffee and cocoa beans during processing (Pardo et al, 1991 ). It has been found that production of pectolytic enzymes in yeasts is a constitutive property and does not require pectin and polygalacturonic acid to induce the synthesis of these enzymes, whereas certain species like C. albidus (Federici, 1985 ), G. lactis (Pardo et al, 1991 ) and K. fragilis (Garcia-Garibay et al, 1987 ) are inducible.…”

“…Dissolved oxygen also plays an important role in production of pectic enzymes from yeasts. The pectolytic activities in strains like K. marxianus (Barnby et al, 1990 ), K. fragilis (Garcia-Garibay et al, 1987 ) and K. lactis (Murad and Foda, 1992 ) were detected when they are grown without shaking and also in anaerobic conditions and the activity was abolished at high aeration rates. It has also reported that decrease in dissolved oxygen concentration in culture medium increases the rate of pectin decomposition by Saccharomycopsis fibuligera (Fellows and Worgan, 1984 ).…”