Production of fungal endoinulinase in a stirred tank reactor and fructooligosaccharides preparation by crude endoinulinase

Abstract

Endoinulinase production from raw Asparagus inulin by Aspergillus tritici was carried out in a laboratory scale fermenter to optimize process variables, viz. aeration (0.57–1.42 vvm), agitation (166–334.09 rpm) and fermentation time (4.63–11.36 Days). Process variables at optimal levels (aeration 1.00 vvm, agitation 166 rpm and fermentation time 8 days) supported maximum (40.27 IU/mL) endoinulinase yield. Nearly, 1.6-fold increase in endoinulinase production was recorded in fermenter after optimization in comparison to shake-flask fermentations. Statistical model elements, viz. F value (1411.10 and 1511.00), adequate precision (102.995 and 107.197), Lack of fit (9.338E-003 and 0.29) and co-efficient of determination (0.9982 and 0.9985) for endoinulinase production and biomass yield are in accordance to the fitted designed model. Thin layer chromatography analysis confirmed the endo-acting nature of the biocatalyst. Fructooligosaccharides (62.41%) containing 18.08% kestose, 13.92% nystose, 6.10% fructofuranosylnystose and 24.31% fructooligosaccharides of varied degree of polymerization (5–9) was obtained from inulin using crude endoinulinase.