Statistical optimization of simple cultures conditions to produce biomass of an ochratocigenic mould biocontrol yeast strain

PELINSKI, R; CERRUTTI, P; PONSONE, M.L; CHULZE, S; GALVAGNO, M

LETTERS IN APPLIED MICROBIOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2012 vol. 54 p. 377 - 382

0266-8254

Aim: To maximize biomass production of an ochratoxigenic mould–controlling strain of Lachancea thermotolerans employing response surface methodology (RSM).Methods and Results: Using Plackett–Burman screening designs (PBSD) and central composite designs (CCD), an optimized culture medium containing (g l)1): fermentable sugars (FS), 139Æ2, provided by sugar cane molasses (CMz), (NH4)2HPO4 (DAP), 9Æ0, and yeast extract (YE), 2Æ5, was formulated. Maximal cell concentration obtained after 24 h at 28_C was 24Æ2 g l)1cell dry weight (CDW). The mathematical model obtained was validated in experiments performed in shaken-flask cultures and also in aerated bioreactors. Maximum yield and productivity values achieved were, respectively, of 0Æ23 g CDW⁄ g FS in a medium containing (g l)1): FS, 87Æ0; DAP, 7Æ0; YE, 1Æ0; and of 0Æ96 g CDW l)1 h)1 in a medium containing (g l)1): FS, 150Æ8 plus DAP, 6Æ9. Conclusions: Optimized culture conditions for maximizing yeast biomass production determined in flask cultures were applicable at a larger scale. The highest yield values were attained in media containing relatively low-CMz concentrations supplemented with DAP and YE. Yeast extract would not be necessary if higher productivity is the aim. Significance and Impact of the Study: Cells of L. thermotolerans produced aerobically could be sustainably produced in a medium just containing cheap carbon, nitrogen and phosphorus sources. Response surface methodology allowed the fine-tuning of cultural conditions.