Abstract
An integral and affordable strategy for the simultaneous production of lignin-modifying and carbohydrate active enzymes and organic amendment, with the aid of a saprobe fungus was developed by using olive oil and wine extraction by-products. The polyporal fungus Trametes versicolor was cultivated in soy or barley media supplemented with dry olive mill residue (DOR) as well as with grape pomace and stalks (GPS) in solid state fermentation (SSF). This strategy led to a 4-fold increase in the activity of laccase, the principal enzyme produced by SFF, in DOR-soy media as compared to controls. T. versicolor managed to secrete lignin-modifying enzymes in GPS, although no stimulative effect was observed. GPS-barley media turned out to be the appropriate medium to elicit most of the carbohydrate active enzymes. The reuse of exhausted solid by-products as amendments after fermentation was also investigated. The water soluble compound polymerization profile of fermented residues was found to correlate with the effect of phytotoxic depletion. The incubation of DOR and GPS with T. versicolor not only reduced its phytotoxicity but also stimulated the plant growth. This study provides a basis for understanding the stimulation and repression of two groups of enzymes of industrial interest in the presence of different carbon and nitrogen sources from by-products, possible enzyme recovery and the final reuse as soil amendments.
Highlights
The development of agro-industrial activity over the last 100 years has increased the amount of lignocellulosic products, representing a serious environmental problem in producing countries (Sánchez, 2009)
The polyporal fungus Trametes versicolor was cultivated in soy or barley media supplemented with dry olive mill residue (DOR) as well as with grape pomace and stalks (GPS) in solid state fermentation (SSF)
The analyses performed by ICP show variations in the composition of minerals such as Al, B, Ca, Cd, Cr, Cu, Fe, K, Ni, Zn, Li, Ti and V, which were present in DOR in considerably higher concentrations
Summary
The development of agro-industrial activity over the last 100 years has increased the amount of lignocellulosic products, representing a serious environmental problem in producing countries (Sánchez, 2009). As a result of these agro-industrial activities, millions of tonnes of these wastes are produced every year, which need to be managed appropriately in order to avoid adverse environmental effects. Though not toxic residue themselves, their high organic matter content and the seasonally high production levels can potentially lead to environmental problems (Spigno et al, 2013). Some studies have proposed that grape stalks be used as bio-sorbent material for the removal of toxic compounds, as composting or to obtain high added-value compounds such as phenolic compounds with antioxidant activity, lignin and cellulose (Spigno et al, 2008)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
