Optimization of ethanol fermentation from discarded carrots using immobilized Saccharomyces cerevisiae
Tóm tắt
Discarded carrots are a valuable source of biomass amenable for valorization. Their use as raw material for ethanol production by fermentation, using yeasts immobilized in Calcium alginate, was proposed. The biocatalyst immobilization method, the existence of internal and external mass transfer limitations, the effect of the initial pH and the reuse of immobilized yeasts were particularly evaluated. Results indicate that beads made with a 2 % solution of Sodium alginate and a 30 % solution of Saccharomyces cerevisiae were strong enough to allow an efficient nutrient transfer into the matrix and to prevent cell leaking. A stirring rate of 200 rpm was needed to avoid external mass transfer limitations. These beads were used in three successive fermentations. An initial pH of 5.5 reached the best fermentation parameters. Non-enriched, non-sterile carrot must was fermented through immobilized yeasts; and values of ethanol concentration (29.9 g L−1), Y
p/s (0.409 g g−1), and productivity (7.45 g L−1 h−1) were obtained. These values were similar to those registered when free cells were used.
Tài liệu tham khảo
Ghorbani, F., Younesi, H., Esmaeili Sari, A., Najafpour, G.: Cane molasses fermentation for continuous ethanol production in an immobilized cells reactor by Saccharomyces cerevisiae. Renew. Energy. 36, 503–509 (2011)
Cardona, C., Sánchez, O.: Fuel ethanol production: process design trends and integration opportunities. Bioresour. Technol. 98, 2415–2457 (2007)
Talebnia, F., Karakashev, D., Angelidaki, I.: Production of bioethanol from wheat straw: an overview on pretreatment, hydrolysis and fermentation. Bioresour. Technol. 101, 4744–4753 (2010)
Brethauer, S., Wyman, C.E.: Review: continuous hydrolysis and fermentation for cellulosic ethanol production. Bioresour. Technol. 101, 4862–4874 (2010)
González-García, S., Gasol, C., Gabarrell, X., Rieradevall, J., Moreira, M.T., Feijoo, G.: Environmental aspects of ethanol-based fuels from Brassica carinata: a case study of second generation ethanol. Renew. Sustainable. Energy. Revi. 13, 2613–2620 (2009)
Aimaretti, N., Ybalo, C., Rojas, M.L., Plou, F.J., Yori, J.C.: Production of bioethanol from carrot discards. Bioresour. Technol. 123, 727–732 (2012)
Aimaretti, N., Ybalo, C.: Valorization of carrot and yeast discards for the obtention of ethanol. Biomass. Bioenerg. 42, 18–23 (2012)
Aimaretti, N., Clementz, A., Codevilla, A., Rojas, M.L., Yori, J.C.: Sustainable fermentation processing of two revalorized agro-industrial discards: carrot and brewer’s yeast. Int. J. of Energy Environ. Eng. 4 24, 1–7 (2013)
Vasconcelos, J.N., Lopes, C.E., Franca, F.P.: Continuous ethanol production using yeast immobilized on sugar-cane stalks. Braz. J. Chem. Eng. 21, 357–365 (2004)
Draget, K.I., Skjak-Brak, G., Smidsrod, O.: Alginate based new materials. Int. J. Biol. Macromol. 21, 47–55 (1997)
Idris, A., Suzana, W.: Effect of sodium alginate concentration, bead diameter, initial pH and temperature on lactic acid production from pineapple waste using immobilized Lactobacillus delbrueckii. Process. Biochem. 41, 1117–1123 (2006)
Yan, J., Bajpai, R., Iannoti, E., Popovic, M., Mueller, R.: Lactic acid fermentation from enzyme-thinned starch with immobilized Lactobacillus amylovorus. J. Chem. Biochem. Eng. 15(2), 59–63 (2001)
Carvalho, W., Silva, S.S., Santos, J.C., Converti, A.: Kylitol production by Ca alginate entrapped cells: comparison of different fermentation systems. Enzyme Microb. Technol. 32, 553–559 (2003)
Prasad, B., Mishra, I.M.: On the kinetics and effectiveness of Immobilized whole cell batch cultures. J. Bioresour. Technol. 53, 269–275 (1995)
Najafpour, G., Younesi, H., Ku Ismail, K.S.: Ethanol fermentation in an immobilized cell reactor using Saccharomyces cerevisiae. Bioresour. Technol. 92(3), 251–260 (2004)
Yu, J., Zhang, X., Tan, T.: Optimization of media conditions for the production of ethanol from sweet sorghum juice by immobilized Saccharomyces cerevisiae. Biomass. Bioenerg. 33, 521–526 (2004)
Colin, R., Bjorn, K.: Basic biotechnology, 2nd edn. Cambridge University Press, Cambridge (2002)
Park, J.K., Chang, H.N.: Microencapsulation of microbial cells. Biotechnol. Advances. 18, 303–319 (2000)
Lee, K.H., Choi, I.S., Kim, Y.-G., Yang, D.-J., Bae, H.-J.: Enhanced production of bioethanol and ultrastructural characteristics of reused Saccharomyces cerevisiae immobilized calcium alginate beads. Bioresour. Technol. 102, 8191–8198 (2011)
Gilson, C.D., Thomas, A.: Ethanol production by alginate immobilized yeast in a fluidized bed bioreactor. J. Chem. Technol. Biotechnol. 62, 38–45 (1995)
Ercan, Y., Irfan, T., Mustafa, K.: Optimization of ethanol production from carob pod extract using immobilized Saccharomyces cerevisiae cells in a stirred tank bioreactor. Bioresour. Technol. 135, 365–371 (2013)
Roukas, T.: Continuous ethanol production from carob pod extract by immobilized Saccharomyces cerevisiae in a packed-bed reactor. J. Chem. Technol. Biotechnol. 59, 387–393 (1994)
Kourkoutas, Y., Bekatorou, A., Banat, I.M., Marchant, R., Koutinas, A.: Immobilization technologies and support materials suitable inalcohol beverages production: a review. Food Microbiol. 21, 377–397 (2004)
Buzas, Z., Dallmann, K., Szajani, B.: Influence of pH on the growth and ethanol production of free and immobilized Saccharomyces cerevisiae cells. Biotechnol. Bioeng. 34, 882–884 (1989)