SHORT COMMUNICATIONS Pullulan production by Aureobasidium pullulans cells immobilized on ECTEOLA-cellulose Thomas P. West Received: 9 May 2010 / Accepted: 29 July 2010 / Published online: 13 August 2010 # Springer-Verlag and the University of Milan 2010 Abstract Cells of the fungus Aureobasidium pullulans ATCC 42023 were immobilized by adsorption on the ion- exchange resin ECTEOLA (epichlorohydrin triethanol- amine)-cellulose and the immobilized cells were examined for their ability to produce the polysaccharide pullulan using batch fermentation. It was found that the cells immobilized on the ECTEOLA-cellulose at pH 2.0 pro- duced higher pullulan levels than those cells immobilized at pH 3.0, 4.0, 5.0, 6.0 and 7.0 after 72 h at 30°C. The pH 2.0- immobilized cells were capable of producing pullulan for 2 cycles of 168 h. Pullulan production by the immobilized cells decreased slightly during the second production cycle but the difference in production was not statistically significant after 168 h. Keywords Pullulan . Immobilization . Ion-exchanger . Adsorption . Aureobasidium Introduction The fungus Aureobasidium pullulans synthesizes the extracel- lular polysaccharide pullulan from various carbon sources (Bernier 1958; Ueda et al. 1963; Catley 1971). The structure of the polysaccharide involves cross-linked maltotriose and maltotetraose residues (Sowa et al. 1963; Catley 1970; Taguchi et al. 1973; Zajic and LeDuy 1973; Catley et al. 1986). A number of potential commercial applications exist for pullulan including use as a food additive, a flocculant, a packaging film, a blood plasma substitute, an adhesive and a dielectric material (Zajic and LeDuy 1977; Singh et al. 2008). Prior studies have examined the immobilization of A. pullulans cells by adsorption on solid supports as well as by entrapment. Sucrose-grown cells of A. pullulans strain 2552 have been immobilized on the solid support diatoma- ceous earth and were shown to be capable of producing pullulan (Mulchandani et al. 1989). Other studies have shown that corn syrup-grown cells of A. pullulans ATCC 42023 could be immobilized using diatomaceous earth, diethylaminoethyl- cellulose or sponge cubes (West and Strohfus 1996a, b). Cell immobilization using the sponge cubes appeared to be a particularly effective method for several cycles of polysac- charide production (West and Strohfus 1996b). Entrapment of A. pullulans cells in polyurethane foam or in a plastic composite support has been reported with the immobilized cells shown to produce pullulan (Mulchandani et al. 1989; Cheng et al. 2010). Although a composite agar layer- microporous membrane system devised to immobilize A. pullulans glucose-grown cells did not prove feasible for pullulan production (Lebrun et al. 1994), other studies have shown that agar-entrapped or alginate-entrapped A. pullulans cells could be used for polysaccharide production (West 2000; West and Strohfus 2001; Urkut et al. 2007). In the present work, pullulan production by corn syrup- grown cells of A. pullulans ATCC 42023 immobilized on the ion-exchange resin ECTEOLA (epichlorohydrin trie- thanolamine)-cellulose was studied using batch fermenta- tion. The reusability of these fungal cells immobilized on ECTEOLA-cellulose for batch pullulan production was also examined. Materials and methods Aureobasidium pullulans ATCC 42023 was the strain utilized in this work (Zajic and LeDuy 1973). The culture medium was prepared as described previously (West and T. P. West (*) Department of Biology and Microbiology, South Dakota State University, Brookings, SD 57007, USA e-mail: Thomas.West@sdstate.edu Ann Microbiol (2010) 60:763–766 DOI 10.1007/s13213-010-0115-3