|1204-1||SELECTION OF CARBON AND NITROGEN SOURCES FOR LIPASE PRODUCTION BY SUBMERGED FERMENTATION WITH A Penicillium sp. ISOLATE|
|Autores:||Priscila Ferreira Pires Eustachio (UFVJM - Universidade Federal dos Vales do Jequitinhonha e Mucuri) ; Alexandre Soares dos Santos (UFVJM - Universidade Federal dos Vales do Jequitinhonha e Mucuri) ; Lilian Araújo Pantoja (UFVJM - Universidade Federal dos Vales do Jequitinhonha e Mucuri) ; Ana Paula de Figueiredo Conte Vanzela (UFVJM - Universidade Federal dos Vales do Jequitinhonha e Mucuri) |
Lipases are special enzymes which hydrolyse acilglycerols in the interface oil/ water. They present several applications and can be produced by microbial fermentations. This work aimed to determine the lipase activity produced by Penicillium sp. T9.1 in response to carbon and nitrogen sources, and its values that could be used to improve the fermentative process. Lipase was produced in submerged fermentations supplemented with soy or maize oils, and yeast extract or ammonium sulphate. Conditions were also varied according to a factorial planning 2n with 4 variables (2 levels): soy (2-3%); maize (2-3%) and olive (2-3%) oils; ammonium sulphate (1-2 g/l). 16 fermentations combining high and low levels of each variable, and 4 central value fermentations were conducted (30º, 150 rpm). Lipase was determined in the filtrates by titration after triglyceride hydrolysis. Determinations were performed in triplicate. In the first fermentations, the highest activities were produced in media supplemented with soy oil/ ammonium sulphate (1.3 U . ml-1 . Min-1 ± 0.22) and soy oil/ yeast extract (1.3 U . ml-1 . Min-1 ± 0.09) after 72 h. Activities decreased in media supplemented with maize oil, especially when the nitrogen source was ammonium sulphate (0.9 U . ml-1. Min-1± 0.04; 96 h) Data from planned fermentations were analyzed with the software Statistica 7.0. Combination of soy (2%), maize (3%) and olive oils (2%) with ammonium sulphate (2%) yielded an activity of 1.5 U . ml-1 . Min-1 ± 0.14 (72 h). Soy oil presented a significant effect on lipase production, whereas its low level was better for the process. Ammonium sulphate also showed a significant effect, and its highest level (2%) was better for lipase production. A significant and negative interaction of maize oil and ammonium sulphate was verified by statistical analysis, in agreement with data obtained in the first fermentations. Thus, soy oil and ammonium sulphate were selected for lipase production by Penicillium sp. T9.1. It was also concluded that 72 h of fermentation was needed to obtain maximum enzyme activity. Factorial planning allowed to confirm the significant variables (soy oil and ammonium sulphate) and its levels that should be combined in a further central composite design (ccd) for process improvement.
Palavras-chave: carbon source, fermentation, lipase, nitrogen source, Penicillium sp.