Production of Fructooligosaccharides by Aspergillus phoenicis Biofilm on Polyethylene as Inert Support
Guilherme Aziani1, Héctor Francisco Terenzi2, João Atílio Jorge2 and Luis Henrique Souza Guimarães2*
1Chemistry Department, Faculty of Philosophy, Science and Letters of Ribeirão Preto, São Paulo University, Avenida Bandeirantes, 3900-Monte Alegre, 14040-901 Ribeirão Preto, São Paulo, Brazil
2Biology Department, Faculty of Philosophy, Science and Letters of Ribeirão Preto, São Paulo University, Avenida Bandeirantes, 3900-Monte Alegre, 14040-901 Ribeirão Preto, São Paulo, Brazil
Article history:
Received April 12, 2010
Accepted February 4, 2011
Key words:
fructooligosaccharides, kestose, nystose, Aspergillus sp., biofilm
Summary:
Aspergillus phoenicis biofilms on polyethylene as inert support were used to produce fructooligosaccharides (FOS) in media containing 25 % (m/V) of sucrose as a carbon source. The maximum production of total FOS (122 mg/mL), with 68 % of 1-kestose and 32 % of nystose, was obtained in Khanna medium maintained at 30 °C for 48 h under orbital agitation (100 rpm). At high concentrations of sucrose (30 %, m/V), the recovery of FOS was higher than that observed at a low concentration (5 %, m/V). High levels of FOS (242 mg/mL) were also recovered when using the biofilm in sodium acetate buffer with high sucrose concentration (50 %, m/V) for 10 h. When the dried biofilm was reused in a fresh culture medium, there was a recovery of approx. 13.7 % of total FOS after 72 h of cultivation at 30 °C, and 10 % corresponded to 1-kestose. The biofilm morphology, analyzed by scanning electron microscope, revealed a noncompact mycelium structure, with unfilled spaces and channels present among the hyphae. The results obtained in this study show that A. phoenicis biofilms may find application for FOS production in a single-step fermentation process, which is cost-effective in terms of reusability, downstream processing and efficiency.
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