Vegetal waste degradation by microbial strains inoculation Degradación de residuos vegetales mediante inoculación con cepas microbianas

(Received: 2013/03/31 - Accepted: 2013/06/02) Vegetal waste treatment product of urban, agricultural and industrial processes has severaltechnical problems and constitutes a significant environmental concern. Among them are thepersistence of crop protection products in high concentrations in plant material and the lack ofmicroorganisms that can tolerate such compounds and efficiently decompose the substrate.Bacteria and mainly white rot fungi are the main decomposers of lignin because of their ability tosynthesize extracellular hydrolytic and oxidative enzymes in large quantities. Trichodermareesei, Aspergillus niger, Penicillium sp. and Phanerochaete chrysosporium strains are modelstrains whose hight degradation efficiency with lignocellulose materials even in the presence ofpollutants has been proven. Several studies such as directed mutagenesis, co-culturing andheterologous expression have been done in order to improve the content of some enzymes(cellulase, xylanase, and β-glucosidase) in model strains, additionally it has been done newgenetic searches to find other microorganisms with this potential. Its main applications are theindustrial production of ethanol and some seconday metabolites under controlled conditions infermentation processes. This review provides an overview about strategies and methodologiescurrently used for vegetal waste utilization by inoculation of microbial strains. (Recibido: 2013/03/31 - Aceptado: 2013/06/02) El tratamiento de los residuos vegetales producto de desechos urbanos, procesos agrícolas eindustriales enfrenta varios problemas técnicos y constituye una preocupación ambientalimportante. Entre ellos se destacan la permanencia de productos fitosanitarios en altasconcentraciones en el material vegetal unido a la carencia de microorganismos que puedantolerar dichos compuestos y logren descomponer eficientemente el sustrato. Las bacterias yprincipalmente los hongos de la podredumbre blanca son los mejores degradadores demateriales lignocelulósicos por su capacidad de sintetizar enzimas extracelulares hidrolíticas yoxidativas en altas cantidades. Trichoderma reesei, Aspergillus niger, Penicillium sp. yPhanerochaete chrysosporium son cepas modelo cuya eficiencia de degradación de materialesricos en lignocelulosa incluso en presencia de contaminantes ha sido comprobada. Se estánrealizando varios estudios de mutagénesis dirigida, co-cultivo y expresión heteróloga, con elobjeto de mejorar el contenido de enzimas (celulasas, xylanasas, y β-glucosidasas) en variascepas, además de nuevas búsquedas genéticas para encontrar otros