Volume 16
Issue 2
Biotechnology
JOURNAL OF
POLISH
AGRICULTURAL
UNIVERSITIES
Available Online: http://www.ejpau.media.pl/volume16/issue2/abs-03.html
THE EFFECT OF AGITATION ON PULLULAN PRODUCTION BY A WHITE MUTANT AUREOBASIDIUM PULLULANS B-1 IN BATCH CULTURE
Małgorzata Gniewosz, Karolina Kraśniewska, Alicja Synowiec
Warsaw University of Life Science – SGGW
Department of Biotechnology, Microbiology and Food Evaluation
ABSTRACT
In this study we indicated a way of producing pullulan using a new strain
of Aureobasidium pullulans, the white mutant B-1. The fungus culture
was run in a stirred bioreactor. Five different impeller speeds were applied:
200 rpm, 400 rpm, 600 rpm, 800 rpm, and 1000 rpm. The kinetics of changes in
air saturation of medium, the content of pullulan, cell biomass, residual sugar
and pH were investigated. The maximum concentrations of pullulan (26.2
g×dm-3)
and biomass (14.4 g d.w.×dm-3), and the maximum saccharose
consumption (>99%) were achieved in the culture stirred at 800 rpm after 96h
of incubation. In this culture, air saturation (DO) has decreased to 45–50% within
36h. That DO value was maintained until the end of fermentation. The pH value
has decreased from an initial 6.5 to 5.35. Agitation speeds in the range of 200–600
rpm and at 1000 rpm were not so beneficial. The respective cultures were characterized
by both: lower biomass yield and lower pullulan content. The B-1 mutant culture
with adjusted pH, maintained at 6.5, and agitation rate of 800 rpm was more
beneficial for biomass growth (18.5 g d.w.×dm-3) than for pullulan production
(16.2 g×dm-3). The data demonstrated that agitation speed influenced pullulan
biosynthesis by A. pullulans B-1. Mutant B-1 is suggested as a potential
candidate for industrial pullulan production.
Key words: pullulan, Aureobasidium pullulans, white mutant, stirred bioreactor.
Małgorzata Gniewosz
Warsaw University of Life Science – SGGW
Department of Biotechnology, Microbiology and Food Evaluation
phone +48 22 5937650
ul. Nowoursynowska 159, bud. 32
02-776 Warszawa, Poland
email: malgorzata_gniewosz@sggw.pl
Karolina Kraśniewska
Warsaw University of Life Science – SGGW
Department of Biotechnology, Microbiology and Food Evaluation
ul. Nowoursynowska 159, bud. 32
02-776 Warszawa, Poland
Alicja Synowiec
Warsaw University of Life Science – SGGW
Department of Biotechnology, Microbiology and Food Evaluation
ul. Nowoursynowska 159, bud. 32
02-776 Warszawa, Poland
Responses to this article, comments are invited and should be submitted within three months of the publication of the article. If accepted for publication, they will be published in the chapter headed 'Discussions' and hyperlinked to the article.