This study analyzed some alternatives to the valorization of agricultural residues considering its use in the treatment of colored effluents. The acid-base behavior of the banana peel surface was thus determined in order to establish the feasibility of its use as a bioadsorbent for dyes. The adsorption capacity of Acid Black 1 was evaluated, through the equilibrium isotherm and the kinetics of this uptake process was also analyzed. Additionally, banana peel was used as substrate-support to evaluate the growth of Inonotus sp SP2, Stereum hirsutum RU 104 and Pleurotus eryngii IJFM 169 and their ligninolytic enzymes production. The decolourization ability of strain fungi was moreover screened. The concentration of functional basic groups in the banana peel surface was determined in 5.5 mmol g -1 as six and a half times higher than acid groups, while the lowest value of the maximum adsorption capacity of Acid Black 1 was 250 mg g -1 . The adsorption kinetics of this dye was suitably represented by a pseudo second order model, obtaining correlation coefficients greater than 0.98. Additionally, the banana peel was demonstrated to be a source of carbon available for growth of the fungi studied. Reducing sugars supplied for banana peel were abruptly consumed up to the 5th day by S. hirsutum and Inonotus sp, while a slower consumption was observed in the case of P. eryngii. Manganese Peroxidase was produced by the three fungal strains, Inonotus sp. additionally produces Laccase and Aryl-alcohol oxidase.Screening assays showed that all of the dyes were decolorized, resulting in efficiencies between 50 and 99% by the three strains, with the exception of Basic Violet 4. Acid Black 1 was decolorized efficiently by Inonotus sp and S. hirsutum. In conclusion, banana peel is a promising material for development of an integral bioremediation strategy for wastewater containing hazardous compounds.

The goal is to determinate the technical feasibility of using agroindustrial wastes for adsorption of dyes. The pHpzcof Brewer’s spent grains and Orange peel is 5.3 and 3.5, respectively. The equilibrium isotherms of Basic Blue 41, Reactiive Black 5, and Acid Black 1 were carried out without pHs control which ranging between 4 and 5.5. The equilibrium concentrations for both adsorbents were fitted by the Freundlich and Langmuir models. The maximum adsorption capacity measured for Basic Blue 41, Reactive Black 5, and Acid Black 1 was 32.4, 22.3, and 19.8 mg g-1for Brewer’s spent grains; and 157, 62.6, and 45.5 for orange peel, respectively. The kinetic of process was fitted by the model of pseudo-second order. The constant rate for orange peel decreased to extend the initial concentration of dye increased, obtaining 4.08 * 10−3−0.6 * 10−3(Basic Blue 41), 2.98 * 10−3−0.36 * 10−3(Acid Black 1), and 3.40 * 10−3−0.46 * 10−3 g mg−1 min−1(Reactive Black 5). The best removal efficiency was obtained in orange peel with values started from 63% to 20%. Consequently, according the results obtained there are two positive effects, the reuse of agricultural wastes and its use as low-cost adsorbent of the dyes.

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Interest in production of ligninolytic enzymes has been growing over recent years for their use in various applications such as recalcitrant pollutants bioremediation; specifically, versatile peroxidase (VP) presents a great potential due to its catalytic versatility. The proper selection of the fermentation mode and the culture medium should be an imperative to ensure a successful production by an economic and available medium that favors the process viability. VP was produced by solid-state fermentation (SSF) of Pleurotus eryngii, using the agricultural residue banana peel as growth medium; an enzymatic activity of 10,800 U L(-1) (36 U g(-1) of substrate) was detected after 18 days, whereas only 1800 U L(-1) was reached by conventional submerged fermentation (SF) with glucose-based medium. The kinetic parameters were determined by evaluating the H2O2 and Mn(2+) concentration effects on the Mn(3+)-tartrate complex formation. The results indicated that although the H2O2 inhibitory effect was observed for the enzyme produced by both media, the reaction rates for VP obtained by SSF were less impacted. This outcome suggests the presence of substances released from banana peel during the fermentation, which might exhibit a protective effect resulting in an improved kinetic behavior of the enzyme.