The effect of fermentation medium composition on lipase production by yeast Candida utilis

Abstract

In this work lipolytic activity of various microorganisms isolated from spoiled soybean oil was studied. Wild yeast strain identified as Candida utilis was chosen for the producing microorganism based on the activity shown on tributyrin agar plate. Studies were undertaken to improve lipase production by optimizing fermentation medium composition. A response surface approach has been used to optimize medium constituents namely maltose, oleic acid, Tween 80Ò and hydrolyzed casein due to the preliminary investigations in which they had positive effect on lipase production. Dependence of lipase production of medium constituents was explained with second order regression equation. Based on the coefficient values comparison, Tween 80Ò concentration has strongest influence on lipase production, followed by oleic acid concentration and then maltose concentration while the influence of hydrolyzed casein concentration was negligible. It was shown that optimization of fermentation conditions can lead to a significant improvement on the lipase production. .

U radu je ispitana lipolitička aktivnost kvasca identifikovanog kao Candida utilis koji je izabran kao lipolitički najaktivniji soj među nekoliko različitih mikroorganizama izolovanih iz pokvarenog sojinog ulja. Ispitan je uticaj sastava fermentacione podloge na mogućnost povećanja produkcije lipaza u odnosu na pokazanu lipolitičku aktivnost u sladnom bujonu kao univerzalnom kvaščevom medijumu. Optimizacija sastava hranljive podloge izvršena je prema rotatabilnom četvorofaktornim eksperimentalnim planom na pet nivoa prema kojem su varirane koncentracije maltoze, oleinske kiseline, Tweena 80Ò i hidrolizata kazeina za koje je u preliminarnim ispitivanjima pokazano da stimulišuće deluju na produkciju lipaza. Zavisnost produkcije lipaza od sastava fermentacione podloge opisana je regresionim modelom drugog reda, a na osnovu vrednosti signifikantnih koeficijenata regresije utvrđeno je da na povećanje produkcije lipaza najveći uticaj ima emulgator Tween 80Ò, zatim oleinska kiselina i na kraju maltoza dok je uticaj koncentracije hidrolizata kazeina zanemarljiv. Pokazano je da se pažljivim izborom sastava hranljive podloge prinos produkovanih lipaza može višestruko uvećati. .