Screening of biocatalysts for transformation of sucrose to fructooligosaccharides

• FTase production by molds, yeasts and bacteria is demonstrated.
• FTase from A. flavus generated upto 63% (w/w) of FOS from sucrose.
• Major fructooligosaccharides produced were GF2 (kestose), GF3 (nystose) and GF4 (fructofuranosyl-nystose).

Twenty microorganisms comprising of sixteen molds, two yeasts and two bacteria were evaluated for their ability to produce fructosyltransferase (FTase) and generate fructooligosaccharides (FOS) from sucrose. FTase production by these microorganisms was studied over a period of 120 h on medium containing 20% (w/v) sucrose as the sole carbon source. High FTase levels (35–31 U/ml) were observed in culture filtrates of Aspergillus flavus, Aspergillus niger, Aspergillus terreus and Penicillium islandicum. Higher concentrations of FOS were generated from 50% (w/v) sucrose using culture filtrates of A. flavus NFCCI 2364 (63.40%, w/w), A. niger SI 19 (54.94%, w/w), A. flavus NFCCI 2785 (44.61%, w/w), P. islandicum MTCC 4926 (43.56%, w/w), A. terreus NFCCI 2347 (24.17%, w/w) and Fusarium solani NFCCI 2315 (15.25%, w/w). Kestose, nystose and 1-fructofuranosyl nystose were the predominant oligosaccharides as revealed by HPLC analysis.

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