36B-23 |
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H. A. RUÍZ-LEZA, Univ. Autonoma de Coahuila, Food Research Dept. School of Chemistry, PO Box 252, Saltillo, Coahuila, 25000, Mexico, R. M. Rodriguez-Jasso, Food Research Dept. School of Chemistry, Univ. Autonoma de Coahuila, PO Box 252, Saltillo, 25000, Mexico, J. C. Contreras-Esquivel, Food Research Dept. School of Chemistry, Univ. Autónoma de Coahuila, PO Box 252, Saltillo, Coahuila, 25000, Mexico, R. Rodriguez-Herrera, Food Research Dept. School of Chemistry., Univ. Autónoma de Coahuila, PO Box 252, Saltillo, Coahuila, 25001, Mexico, and C. N. Aguilar, Univ. Autonoma de Cohuila, Food Research Dept. School of Chemistry, PO Box 252, Saltillo, Coahuila, 25000. Substrates used in solid state fermentation (SSF) need to be economical and easy to acquire agroindustrial wastes as Mexican lime peel can be used in order to obtain higher value products as enzymes. SSF substrate require characteristics that allow to filamentous fungi maintain good invasion capacity over the culture matrix, being the support particle size, one factor that can affect microorganisms growth, although this characteristic has been scarcely studied. Pectinases have been applied in food and pharmaceutical industries, but nowadays they play an important role in the study of phenomenon recognition of polysaccharides at molecular level. The objective was to determinate the effect of lime peel pomace (LPP) particle size in 8 filamentous microorganisms growth isolated from Mexican semi-desert and to evaluate pectinase production in SSF using LPP as substrate. LPP was prepared by clean technology. The particle sizes used were mesh 10, 25, 50, and 80. The microorganisms with highest support invasion capacity and the particle size were selected by radial growth. SSF was realized at 70% humidity percent of Czapek-Dox culture medium, selected strain (Aspergillus niger Aa-20) was inoculated and the kinetic follow each 12 h. for 98 h. The data was modeled by logistic equation. A. niger Aa-20 showed the highest growth rate, 0.68 h-1, mesh 25 allowed the highest growth (0.099 h-1). Consumption of the substrate decreased drastically after 24 h. (7.04% total sugars) and stabilized at 60 h. (1.66% total sugars).The maximum pectinase activity was at 24 h (21236 U/L). The R value was 0.97 with a Xm of 1.76 and µ of 0.09. In conclusion, each LPP particle size has different properties that affect the microorganism capacity invasion. Nutritional composition is directly related to particle size and affects the growth of microorganisms. LPP as substrate gave good results of pectinase activity at 24 h.
Session 36B, Biotechnology: General
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |