Fundação para a Ciência e
Tecnologia (FCT

Brányik, Tomáš

Mota, André

Silva, Daniel Pereira da

Teixeira, J. A.

Vicente, A. A.

Universidade do Minho: RepositoriUM

 INFLUENCE OF DIFFERENT PRE-TREATMENT METHODS ON THE IMMOBILIZATION OF BREWER’S YEAST ON CORN COB PARTICLES  André Mota1, Daniel P. Silva1, Tomáš Brányik2, António A. Vicente1, José A. Teixeira1  1. IBB - Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, University of Minho,  4710-057 Braga PORTUGAL, email: amota@deb.uminho.pt 2. Department of Fermentation Chemistry and Bioengineering, Institute of Chemical Technology Prague,  Technická 5, 166 28 Prague 6, CZECH REPUBLIC  Keywords: Fermentation, Immobilization, Corn cobs  Introduction. Immobilized cell systems have been successfully applied in the production of several biotechnological products, including the continuous production of beer. In previous years, cellulose-based carriers have been successfully applied and their importance as a carrier for continuous fermentations has increased as a consequence of their properties. Besides, previous studies have demonstrated the corn cobs capacity for yeast cells immobilization1. Being a suitable material for immobilization, corn cobs are also cheap and available in a large amount2.  Thus, the main aim of this work was to evaluate the effect of different pre-treatment methods on yeast cells immobilization for different conformations of corn cobs particles. Derivatization was used as a procedure to achieve higher adhesion with a decrease on the immobilization time.  Methods. The corn cobs used on this work had three different conformations: cylinders (CC1); ¼ of cylinders (CC2); and milled corncobs (CC3). Two pre-treatment methods were evaluated, aiming at an increase in the carrier ability to immobilization: 1st Pre-treatment using hydrolysis with 1 % (v/v) HCL solution at 60 ºC followed by delignification with 1 % (v/v) NaOH solution3 and 2nd pre-treatment in which the hydrolysis was performed by thermal treatment at 121ºC for 15 min followed again by delignification (1 % (v/v) NaOH). For each pre-treatment, the derivatization was performed according to Antrim and Harris4. For each experiment, cell suspension was added to the pre-treated carrier, and the decrease in the O.D. (600 nm) of free-cells was measured until stabilization.   Results and discussion. The used technique did not take in account cell growth,, only adhesion values (mechanical or by ion biding) were considered. From Table 1 the immobilization under different conditions can be analysed. It is also possible to see that the derivatization had, in terms of IEC, a major effect for CC3 carrier when using the second treatment. However, and still at this condition, this behaviour was not verified in the immobilization values being these similar regardless of the IEC values. On a few situations the increase of the IEC capacity was accomplished with a decrease of the immobilization time. On the other hand, the evaluation of this process requires that the amount of immobilized biomass is considered beside the immobilization time. Thus, among the pre-treatments without derivatization the 2nd pre-treatment method is the one that gives better results; while among the procedures using derivatization the 1st method appears to be the best.   Table 1. Biomass Immobilization, Ion Exchange capacity (IEC), and Immobilization time (TIMB) for each assay. 1A and 2A – First and second pre-treatment, respectively, without derivatization; 1B and 2B – First and second pre-treatment, respectively, with derivatization  Conclusions.The obtained results demonstrate that the derivatization procedure only had a real effect on biomass immobilization in CC3 particles. When using the first pre-treatment, derivatization influenced all the particles. It can be also be concluded that milled corncobs have a higher immobilization capacity in comparison with other particle conformations  Acknowledgements. The authors thank the financial support from FCT (Fundação para a Ciência e Tecnologia, SFRH/BD/37082/2007) References. 1. Mota, A.; Silva, D.P.; Brányik, T.; Vicente, A.A.; Teixeira, J.A. (2008). Immobilization of yeast cells in corn cobs particles: perliminary studies. VII Brazilian Meeting on Chemistry of Food and Beverages. Lorena, SP 3rd and 4th December. 2. Torre, P.; Aliakbarian, B.; Rivas, B. and Domínguez J. (2008) Release of ferulic acid from corn cobs by alkaline hydrolysis. Biochemical Engineering Journal. 40: 500-506. 3. Brányik, T.; Vicente, A.A.; Machado Cruz, J.M.; Teixeira, J.A. (2002). Continuous Primary Beer Fermentation with Brewing Yeast on Spent Grains. J. Inst. Brew. 108(4): 410-415. 4. Antrim, R. L. and Harris, D.W. (1991) Treatment of cellulosic ion exchange composites in hot aqueous medium to increase adsorption of macromolecules. U.S. Patent 5001063. Carrier Assay TIMB / min IEC / (meq/g) Immobilization / (mgBIOMASS/gCARRIER) 1A 50 0.1281 1.851 1B 40 0.1647 16.613 2A 30 0.0558 5.851 CC1 2B 30 0.0636 6.943 1A 50 0.1487 4.179 1B 40 0.1765 9.758 2A 30 0.0636 4.372 CC2 2B 20 0.1301 5.204 1A 40 0.1317 1.892 1B 40 0.2893 19.038 2A 30 0.1749 3.788 CC3 2B 30 1.1134 20.884 

Influence of different pre-treatment methods on the immobilization of brewer’s yeast on corn cob particles

http://repositorium.sdum.uminho.pt/bitstream/1822/9585/1/OIII-24.pdf

Influence of different pre-treatment methods on the immobilization of brewer’s yeast on corn cob particles

Abstract

Similar works

Full text

Available Versions

Universidade do Minho: RepositoriUM