Production of fructosyltransferase by a local isolate ofAspergillus nigerin both submerged and solid substrate media

Abstract

Screening of microorganisms capable of producing the enzyme fructosyltransferase (FTase) that could be used for the production of fructooligosaccharides (FOS) led to the isolation of a strain of Aspergillus niger. The fungus produced extracellular FTase in both submerged fermentation (SmF) using chemically-defined medium, and solid state fermentation (SSF) using agricultural by-products such as kola nut pod and ripe plantain peel. Maximum enzyme activity of 24.49 Uml−1 was obtained in SmF after 48 h of fermentation, while maximum enzyme activities of 20.77 and 27.77 U g−1 were obtained in SSF using ripe plantain peel and kola nut pod, respectively. The enzyme was used to prepare fructooligosaccharides (FOS), with the maximum yield of 33.24% FOS, consisting of kestose and nystose produced by FTase of kola nut pod fermentation.The safety of prepared FOS was investigated using albino rats. The rats were grouped and fed orally with 2500 mg kg−1 bw/day of FOS, 5000 mg kg−1 bw/day FOS, 2500 mg kg−1 bw/day of ho...