Pullulan-hyperproducing color variant strain of Aureobasidium pullulans FB-1 newly isolated from phylloplane of Ficus sp.

The studies were carried out for the isolation of efficient pullulan producing strains of Aureobasidium pullulans. Five strains were isolated from phylloplane of different plants. Amongst these, three were producing black pigment melanin, while the remaining two produced pink pigment. These two color variant isolates of A. pullulans were designated as FB-1 and FG-1, and obtained from phylloplane of Ficus benjamina and Ficus glometa, respectively. The parameters employed for the identification of the isolates included morphology, nutritional assimilation patterns and exopolysaccharide (EPS) production. Isolates were compared with standard cultures for EPS production. A. pullulans FB-1 was the best producer of pullulan giving up to 1.9, 1.4 and 1.7 times more pullulan than the control of A. pullulans NOM 976, NCIM 1048 and NCIM 1049, respectively. The IR spectra of the isolates and standard strains revealed that the polysaccharide was pullulan, but not aubasidan. The study also supported the fact that A. pullulans is a ubiquitous organism and phylloplane being the important niche of the organism. (C) 2007 Elsevier Ltd. All rights reserved.