The valorization of tequila industry agricultural waste through its use as a substrate for laccase production in a fluidized bed bioreactor

Agave tequilana Weber leaves and fiber were studied as substrates for laccase production by Pleurotus ostreatus in a submerged culture, in order to take advantage of these agro-industriai wastes, which are generated during agave harvesting for tequila production. The optimal conditions for laccase production in submerged fermentation were met by a substrate concentration of 1% (w/v) at 120 h, producing 276.36 and 169.25 U L^-1for leaves and fiber, respectively. The addition of glucose did not significantly (p>0.05) affect enzyme production. A medium consisting of only water and agave leaves was the best culture broth for enzyme production, and this medium was selected for the study with the fluidized bed bioreactor scale. The specific activity for kinetic studies in a flask (50 ml working volume) was 14.68 U mg^-1" In the reactor, the specific activities were 10.78,1.09 and 1.74 U mg^-1" for the first, second and third cycles of operation, respectively. Thus, the leaf residues of A. tequilana generated by the tequila industry can be used as a substrate by P. ostreatus for laccase production without co-substrate addition.