Volume 9
Issue 1
Biotechnology
JOURNAL OF
POLISH
AGRICULTURAL
UNIVERSITIES
Available Online: http://www.ejpau.media.pl/volume9/issue1/abs-20.html
OPTIMIZATION OF CITRIC ACID PRODUCTION FROM GLUCOSE SYRUP BY YARROWIA LIPOLYTICA USING RESPONSE SURFACE METHODOLOGY
Waldemar Rymowicz1, Edmund Cibis2
1 Department of Biotechnology and Food Microbiology,
Wroc³aw University of Environmental and Life Sciences, Poland
2 Department of Bioprocess Engineering,
Wroc³aw University of Economics, Poland
ABSTRACT
A new criterion was proposed to evaluate the process of citric acid biosynthesis by the acetate negative mutant strain Yarrowia lipolytica AWG-7 cultivated on glucose syrup by the repeated-batch method. This criterion imparts the same weight to the overall amount of the citric acid production and to the trend in citric acid concentration. To determine the optimum levels of bacto-peptone, ammonium chloride and potassium dihydrogen phosphate which maximize the proposed objective function, a central composite design was developed using 50 ml repeated-batch fermentation. The design involved 20 processes conducted with various combinations of the five values of these three parameters. The experiments produced empirical values of the proposed criterion which were then approximated with the fourth-order polynomial. It was found that the optimal concentrations of bacto-peptone, ammonium chloride, and potassium dihydrogen phosphate equaled 8.5; 159.8 and 65 mgl-1, respectively.
Key words: Yarrowia lipolytica, glucose syrup, citric acid, response surface methodology, acetate negative mutant.
Waldemar Rymowicz
Department of Biotechnology and Food Microbiology,
Wroc³aw University of Environmental and Life Sciences, Poland
Norwida 25, 50-373 Wroclaw, Poland
Fax. 48-71-3284124
Phone: 48-71-3205143
email: rymowicz@ozi.ar.wroc.pl
Edmund Cibis
Department of Bioprocess Engineering,
Wroc³aw University of Economics, Poland
Komandorska 118/120, 53-345 Wroc³aw, 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.