Effects of nonionic surfactants on pellet formation and the production of β-fructofuranosidases from Aspergillus oryzae KB

- Mycelial growth pellets became small and spherical on addition of Tween surfactant.
- Pellet particle size diminished with increased hydrophobicity (lower HLB values).
- Production of fructosyl-transferase from Aspergillus oryzae was enhanced by Tween 20.
- Filamentous pellet size depended on HLB values of the polyoxyethylene oleyl ethers.
- Polyoxyethylene oleyl ethers had little effect on fructosyl-transferase production.

Aspergillus oryzae KB produces two β-fructofuranosidases (F1 and F2). F1 has high transferring activity and produces fructooligosaccharides from sucrose. Mycelial growth pellets were altered by the addition of Tween 20, 40 and 80 (HLB = 16.7, 15.6 and 15.0, respectively) in liquid medium cultures to form small spherical pellets. The particle size of the pellets decreased with the HLB value, which corresponds to an increase in surfactant hydrophobicity. Selective F1 production and pellet size were maximized using Tween 20. Adding polyoxyethylene oleyl ethers (POEs) with various degrees of polymerization (2, 7, 10, 20 and 50: HLB = 7.7, 10.7, 14.7, 17.2 and 18.2, respectively) was investigated. A minimum mean particle size was obtained using a POE with DP = 10, HLB = 14.7. The POE surfactants had little effect on the selective production of F1. The formation of filamentous pellets depended on the surfactant HLB value, and F1 enzymes were produced most efficiently using Tween 20.