Production of Fungal Pectin Lyase and Polygalacturonase from Fruit Wastes by Solid State Fermentation

Polygalacturonase (PG or PGase) and Pectin lyase (PL) are depolymerase enzymes that split the ?-1, 4-glycosidic linkages in the backbone of homogalacturonans. They are produced by microorganisms degrading pectin-containing substrates. PG and PL were produced in the solid-state fermentation (SSF) of beans testa (BT), mango peels (MP), Plantain peels (PP), and BT: MP: PP (1:1:1). Substrates were seeded with individual fungal strains namely Aspergillus tamarii, Aspergillus terreus, Aspergillus piperis, Aspergillus parasiticus and Mucor piriformis. PG production ranged from 0.0377 - 141.0095 U/g with A. tamarii, A. terreus and A. piperis producing the highest on mango peels. PL production ranged from 50.50 - 10,852.50 U/g with Mucor piriformis producing the highest on plantain peels. The pH of the fermentation medium changed during growth, metabolism, and pectinase production. The best pH for pectinase production falls within the acidic range. Unconventional substrates such as PP are viable for pectinase production, and PL yield in SSF is improved by compositing substrates.

Biotechnological potential of alternative carbon sources for production of pectinases by Rhizopus microsporus var. rhizopodiformis

Fungi collected from Brazilian soil and decomposing plants were screened for pectinase production. R. microsporus var. rhizopodiformis was the best producer and was selected to evaluate the pectic enzyme production under several nutritional and environmental conditions. The pectinase production was studied at 40ºC, under 28 carbon sources-supplemented medium. The inducer effect of several agro-industrial residues such as sugar cane bagasse, wheat flour and corncob on polygalacturonase (PG) activity was 4-, 3- and 2-fold higher than the control (pectin). In glucose-medium, a constitutive pectin lyase (PL) activity was detected. The results demonstrated that R. microsporus produced high levels of PG (57.7 U/mg) and PL (88.6 U/mg) in lemon peel-medium. PG had optimum temperature at 65 ºC and was totally stable at 55 ºC for 90 min. Half-life at 70 ºC was 68 min. These results suggested that the versatility of waste carbon sources utilization by R. microsporus, produce pectic enzymes, which could be useful to reduce production costs and environmental impacts related to the waste disposal.

Pectinase production by Penicillium viridicatum RFC3 by solid state fermentation using agricultural wastes and agro-industrial by-products

Pectin lyase and polygalacturonase production by newly isolated Penicillium viridicatum strain Rfc3 was carried out by means of solid state fermentation using orange bagasse, corn tegument, wheat bran and mango and banana peels as carbon sources. The maximal activity value of polygalacturonase (Pg) (30U.g-1) was obtained using wheat bran as carbon source while maximal pectin lyase (Pl) (2000 U.g-1) activity value was obtained in medium composed of orange bagasse. Mixtures of banana or mango peels with sugar cane bagasse resulted in increased Pg and Pl production compared to fermentations in which this residue was not used. The mixture of orange bagasse and wheat bran (50%) increased the production of Pg and Pl to 55 U.g-1 and 3540 U.g -1 respectively. Fractions of Pg and Pl, isolated by gel filtration in Sephadex G50, presented optimum activity at pH 5.0 and 10.5 respectively. Maximal activity of Pg and Pl fractions was determined at 55ºC and 50ºC respectively. Pg was stable in neutral pH range and at 40ºC whereas Pl was stable in acidic pH and at 35ºC, for 1 h.

A produção de pectina liase (Pl) e poligalacturonase (Pg) por cepa de Penicillium viridicatum Rfc3, recentemente isolada, foi estudada por meio de fermentação em estado sólido usando bagaço de laranja, tegumento de milho, farelo de trigo e cascas de manga e banana como fontes de carbono. Quando os resíduos foram utilizados isoladamente, o valor máximo de atividade de Pg (30 U g-1) foi observado em meio de farelo de trigo, enquanto que o valor máximo para atividade de Pl (2000 U g-1) foi obtido em meio de bagaço de laranja. Misturas de cascas de banana ou de manga com bagaço de cana-de-açúcar (50% p/p), resultaram em aumento na produção tanto de Pl quanto de Pg, quando comparado com os experimentos nos quais esses materiais foram usados isoladamente. A mistura de bagaço de laranja e farelo de trigo (50%) elevou a produção de Pg e Pl para 55 U.g-1 e 3540 U.g-1, respectivamente. O fracionamento das enzimas presentes na solução enzimática bruta, através de filtração em gel Sephadex G50, resultou na obtenção de diferentes frações de Pl e de Pg. As frações de Pg e Pl, as quais foram caracterizadas, apresentaram atividade ótima em pH 5,0 e 10,5, respectivamente. A atividade máxima da fração de Pg foi obtida a 55ºC e, para Pl, a 50ºC. A Pg foi estável em valores de pH próximos à neutralidade e a 40ºC, enquanto que a Pl foi estável em pH ácido e a 35ºC, por uma hora.