Biotecnología

 

Effect of initial substrate/inoculum ratio on cell yield in the removal of hydrophobic vocs in fungal biofilters

 

Efecto de la razón sustrato/inóculo sobre el rendimiento celular en la remoción de covs hidrofóbicos en biofiltros fúngicos

 

A. Vergara-Fernández¹*, J. San Martín-Davison³, L.A. Díaz-Robles², O. Soto-Sánchez³

 

¹ Facultad de Ingeniería y Ciencias Aplicadas, Universidad de los Andes, Mons. Álvaro del Portillo 12455, Las Condes. Santiago, 7620001 Chile * Corresponding author. E-mail: aovergara@miuandes.cl telephone/fax: 56-02-2618 1000.

² Departamento de Ingeniería Química, Facultad de Ingeniería, Universidad de Santiago de Chile.

³ Escuela de Ingeniería Ambiental, Facultad de Ingeniería, Universidad Católica de Temuco.

 

Received September 30, 2013.
Accepted June 19, 2014.

 

Abstract

Different kinetic models have been proposed to describe the elimination of hydrophobic volatile organic compounds (VOCs) by fungal biofiltration. In this process the ratio of the initial substrate concentration (C^p_b0) to the initial biomass (X₀) has been shown to influence the cell yield. This papers presents a study of the efect of the C^p_b0/X₀ ratio on observed cell yield (Y_obs) in a fixed bed batch system (microcosm) using a gaseous carbon source, as an approximation to its application in the fungal biofiltration of hydrophobic VOCs. Essays were carried out in fixed-bed microcosms using the filamentous fungus Fusarium solani as a biological agent and n-pentane as a carbon and energy source. The results indicated that Y_obs in the gas phase is inversely proportional to the C^p_b0/X₀ ratio, with values of 0.9 to 0.35 g_biomass g^-1_pentane being obtained when the C^p_b0/X₀ ratio is changed from 0.1 to 1.0 g_pentane g^-1_biomass. The results indicate that more than 60% of n-pentane was consumed due to energy spilling, and that strong dissociation of catabolism from anabolism occurred at higher C_b0/X₀ ratios.

Keywords: hydrophobic VOCs, fungal biofiltration, substrate/inoculum ratio, growth yield.

 

Resumen

Diferentes modelos cinéticos han sido propuestos para describir la eliminación de compuestos orgánicos volátiles hidrofóbicos (COVs) en biofiltros fúngicos. En este proceso la razón de la concentración inicial de sustrato (C^p_b0) a la biomasa inicial (X₀) ha mostrado influir en el rendimiento celular. Este artículo presenta el estudio del efecto de la razón C^p_b0/X₀ en el rendimiento celular observado (Y_obs) en un sistema por lote de lecho fijo (microcosmo) utilizando una fuente de carbono gaseosa, como una aproximación a su aplicación en la biofiltración fúngica de COVs hidrofóbicos. Los ensayos fueron realizados en microcosmos de lecho fijo utilizando el hongo filamentoso Fusarium solani como agente biológico y n-pentano como fuente de carbono y energía. Los resultados indican que Y_obs en la fase gaseosa es inversamente proporcional a la razón C^p_b0/X₀, con valores de 0.9 a 0.35 g_biomasa g^-1_pentano siendo obtenido cuando la razón C^p_b0/X₀ es cambiada desde 0.1 a 1.0 g_pentano g^-1_biomasa. Los resultados indican que más del 60% del n-pentano fue consumido debido a pérdida de energía, y que una fuerte disociación del catabolismo y anabolismo ocurre para altas razones C^p_b0/X₀.

Palabras clave: COVs hidrofóbicos, biofiltración fúngica, razón sustrato/inoculo, rendimiento de crecimiento.

 

DESCARGAR ARTÍCULO EN FORMATO PDF

 

Acknowledgements

The present research was financed by the CONICYT (National Commission for Scientific and Technological Research) (FONDECYT Project N°11080036).

 

References

Aktas, Ö. (2012). Effect of S₀/X₀ ratio and acclimation on respirometry of activated sludge in the cometabolic biodegradation of phenolic compounds. Bioresource Technology 111, 98104.         [ Links ]

Arriaga, S. and Revah, S. (2009). Mathematical modeling and simulation of hexane degradation in fungal and bacterial biofilters: effective diffusivity and partition aspects. Canadian Journal of Civil Engineering 36, 1919-1925.         [ Links ]

Arriaga, S. and Revah, S. (2005). Removal of n-hexane by Fusarium solani with a gas-phase biofilter. Journal Industrial Microbiology Biotechnology 32, 548-553.         [ Links ]

Chang, J., Chudoba, P. and Capdeville, B. (1993). Determination of the maintenance requirements of activated sludge. Water Science Technology 28, 139-142.         [ Links ]

Devinny, J.S. and Ramesh, J. (2005). A phenomenological review of biofilter models. Chemical Engineering Journal 113, 187-196.         [ Links ]

Dorado, A.D., Baquerizo, G., Maestre, J.P., Gamisans, X., Gabriel, D. and Lafuente, J. (2008). Modeling of a bacterial and fungal biofilter applied to toluene abatement: Kinetic parameters estimation and model validation. Chemical Engineering Journal 140, 52-61.         [ Links ]

Garnier, P.M., Auria, R., Augur, C. and Revah, S. (1999). Cometabolic biodegradation of methyl t-butyl ether by Pseudomonas aeruginosa grown on pentane. Applied Microbiology Biotechnology 51, 498-503.         [ Links ]

González-Vázquez, R., Azaola-Espinosa, A., Osorio-Revilla, G., Gallardo-Velázquez, T., Cruz-Victoria, T., Arana-Errasquin, R. and Rivera-Espinoza, Y. (2011). The effect of different carbon sources and salts in the production of naringinase by Aspergillus niger ATCC1015. Revista Mexicana de Ingeniería Química 10, 1-8.         [ Links ]

Lareo, C., Sposito, A.F., Bossio, A.L. and Volpe, D.C. (2006). Characterization of growth and sporulation of Mucor bacilliformis in solid state fermentation on an inert support. Enzyme Microbial Technology 38, 391-399.         [ Links ]

Liu, Y., Liu, Q.S., and Tay, J.H. (2005). Initial conditions-dependent growth kinetics in microbial batch culture. Process Biochemistry 40, 155-160.         [ Links ]

Liu, Y. (2000). The S₀/X₀ -Dependent dissolved organic carbon distribution in substrate-sufficient batch culture of activated sludge. Water Research 34, 1645-1651.         [ Links ]

Liu, Y., Guang-Hao, C. and Paul, E. (1998). Effect of the S ₀/X₀ ratio on energy uncoupling in substrate-sufficient batch culture of activated sludge. Water Research 31, 2883-2888.         [ Links ]

Liu, Y. and Guang-Hao, C. (1997). Model of energy uncoupling for substrate-sufficient culture. Biotechnology Bioengineering 55, 571-576.         [ Links ]

Liu, Y. (1996). A growth yield model for substrate-sufficient continuous culture of microorganisms. Environmental Technology 17, 649-653.         [ Links ]

Macris, B.J. and Kokke, R. (1978). Continuous fermentation to produce fungal protein. Effect of growth rate on the biomass yield and chemical composition of Fusarium moniliforme. Biotechnology and Bioengineering XX, 1027-1035.         [ Links ]

Maestre, J.P., Gamisans, X., Gabriel, D. and Lafuente, J. (2007). Fungal biofilters for toluene biofiltration: Evaluation of the performance with four packing materials under different operating conditions. Chemosphere 67, 684-692.         [ Links ]

Miller, T.L. and Johnson, M.J. (1966). Utilization of normal alkanes by yeasts. Biotechnology and Bioengineering 8, 549-565.         [ Links ]

Hernández-Meléndez, O., Bárzana, E., Arriaga, S., Hernández-Luna, M., and Revah, S. (2008). Fungal removal of gaseous hexane in biofilters packed with poly (ethylene carbonate) pine sawdust or peat composites. Biotechnology and Bioengineering 100, 864-871.         [ Links ]

Takahashni, J., Uemura, N., and Ueda, K. (1970). Fundamental studies on the cultivation of hydrocarbon-utilizing microorganisms. Part I. Mass balance for bacterial growth on n-pentane. Agricultural and Biological Chemistry 34, 32-37.         [ Links ]

Rene, E.R., Veiga, M.C., and Kennes, C. (2010). Biodegradation of gas-phase styrene using the fungus Sporothrix variecibatus: Impact of pollutant load and transient operation. Chemosphere 79, 221-227.         [ Links ]

Russell, JB. (2007). The energy spilling reactions of bacteria and other organisms. Journal of Molecular Microbiology and Biotechnology 13, 1-11.         [ Links ]

Schellart, J.A. (1975). Fungal protein from corn waste effluents. Mededelingen Landbouwhogeschool Wageningen, Nederland, 75-17.         [ Links ]

Spigno, G. and De Faveri, D.M. (2005). Modeling of a vapor-phase fungi bioreactor for the abatement of hexane: Fluid dynamics and kinetic aspects. Biotechnology and Bioengineering 89, 319-328.         [ Links ]

Spigno, G., Pagella, C., Daria, F.M., Molteni, R. and De Faveri, D.M. (2003). VOCs removal from waste gases: gas-phase bioreactor for the abatement of hexane by Aspergillus niger. Chemical Engineering Science 58, 739-746.         [ Links ]

Vergara-Fernández, A., Hernández, S., Muñoz, R. and Revah, S. (2012). Influence of the inlet load, EBRT and mineral medium addition on spore emission by Fusarium solani in the fungal biofiltration of hydrophobic VOCs. Journal of Chemical Technology and Biotechnology 87, 778-784.         [ Links ]

Vergara-Fernández, A., Hernández, S., San Martín-Davison, J. and Revah, S. (2011). Morphological characterization of aerial hyphae and simulation growth of Fusatium solani under different carbon source for application in the hydrophobic VOCs biofiltration. Revista Mexicana de Ingeniería Química 10, 225-233.         [ Links ]

Vergara-Fernández, A., Soto-Sánchez, O. and Vásquez, J. (2011b). Effects of packing material on n-pentane/biomass partition coefficient for use in fungal biofilters. Chemical and Biochemical Engineering Quarterly 25, 439-444.         [ Links ]

Vergara-Fernández, A., Hernández, S. and Revah, S. (2011). Elimination of hydrophobic volatile organic compounds in fungal biofilters: reducing start-up time using different carbon sources. Biotechnology and Bioengineering 108, 758-765.         [ Links ]

Vergara-Fernández, A., Hernández, S. and Revah, S. (2008). Phenomenological model of fungal biofilter for the abatement of hydrophobic VOCs. Biotechnology and Bioengineering 101, 1182-1192.         [ Links ]

Vergara-Fernaíndez, A., Van Haaren, B. and Revah, S. (2006). Phase partition of gaseous hexane and surface hydrophobicity of Fusarium solani when grown in liquid and solid media with hexanol and hexane. Biotechnology Letters 28, 2011-2017.         [ Links ]

Vigueras, G., Arriaga, S., Shirai, K., Morales, M. and Revah, S. (2009). Hydrophobic response of the fungus Rhinocladiella similis in the biofiltration with volatile organic compounds with different polarity. Biotechnology Letters 31, 1203-1209.         [ Links ]

Wang, J., Fang, F., and Yu, H.Q. (2007). Substrate consumption and biomass growth of Ralstonia eutropha at various S₀/X₀ levels in batch cultures. Bioresource Technology 98, 2599-2604.         [ Links ]

Yamame, T., Hibino, W., Ishihara, K., Kadotani, Y. and Kominami, M. (1992). Fed-batch culture automated by uses of continuously measured cell concentration and culture volume. Biotechnology and Bioengineering 39, 550-555.         [ Links ]

Zhou, Y., Zhang, Z., Nakamoto, T., Li, Y., Yang, Y., Utsumi, M. and Sugiura, N. (2011). Influence of subtrate-to-inoculum ratio on the bacth anaerobic digestion of bean curd refuseokara under mesophilic conditions. Biomass and Bioenergy 35, 3251-3256.         [ Links ]

Zeng, S., Yuan, X., Shi, X. and Qiu, Y. (2010). Effect of inoculum/substrate ratio on methane yield and orthophosphate release from anaerobic digestion of Microcystis spp. Journal of Hazardous Materials 178, 89-93.         [ Links ]