Biotransformation of grape pomace from Vitis labrusca by Peniophora albobadia LPSC # 285 (Basidiomycota).

Grape pomace from Vitis labrusca is an important sub-product of the "American table wine" industry. It is recalcitrant to degradation, and its accumulation is a serious problem with negative environmental impacts. We analyzed the ability of five white-rot fungi to transform this residue in-vitro. Mass loss and phenol removal in grape pomace treated with each fungus were compared after 30-day solid-state fermentation. Since Peniophora albobadia isolate LPSC 285 was the fungus that showed the highest degradative ability and the lowest free phenol levels in the residue transformed, we selected this fungus to monitor its effect on this residue after 30, 60, and 90 days of incubation. We analyzed mass loss of the residue caused by the fungus activity and its chemical changes using Fourier transform infrared spectroscopy. After 90 days of incubation, Peniophora albobadia isolate LPSC 285 reduced grape pomace mass by 20.48%, which was associated with degradation of polysaccharides and aromatic structures. We concluded that Peniophora albobadia LPSC # 285 isolate is a promising fungus to transform grape pomace from Vitis labrusca under solid-state fermentation conditions.

Fungal transformation and reduction of phytotoxicity of grape pomace waste.

Grape pomace (GP) from Vitis labrusca, the main byproduct from "American table wine" production, is recalcitrant to degradation, and its accumulation is a serious problem with negative environmental impacts. In this work, transformation of grape pomace using a steam pretreatment followed by incubation of GP during a 90-day period with six different fungi were evaluated. Several fungi tested reduced the phytotoxicity of water-soluble fraction (WSFd) from steam-pretreated GP after 90 days' incubation to lettuce and tomato seeds. U. botrytis caused the largest effective phytotoxicity reduction of WSFd (used in the concentration range of 10-1.25% p/v) and was the only fungus causing the removal of monoaromatic compounds. Therefore, this procedure with U. botrytis effectively reduces the availability of phytotoxic monoaromatic compounds in GP, which opens a way for the development of guidelines for the management of these wastes and their potential use as organic amendments in agricultural soil.

Fusarium equiseti LPSC 1166 and its in vitro role in the decay of Heterostachys ritteriana leaf litter.

The role of microorganisms in litter degradation in arid and semi-arid zones, where soil and water salinization is one of the main factors limiting carbon turnover and decay, remains obscure. Heterostachys ritteriana (Amaranthaceae), a halophyte shrub growing in arid environments such as "Salinas Grandes" (Córdoba, Argentina), appears to be the main source of organic matter in the area. Little is known regarding the microorganisms associated with H. ritteriana, although they are a potential source of enzymes such as cellulolytic ones, which might be important in biotechnological fields such as bioethanol production using ionic liquids. In the present study, by studying the microbiota growing on H. ritteriana leaf litter in "Salinas Grandes," we isolated the cellulolytic fungus Fusarium equiseti LPSC 1166, which grew and degraded leaf litter under salt stress. The growth of this fungus was a function of the C substrate and the presence of NaCl. Although in vitro the fungus used both soluble and polymeric compounds from H. ritteriana litter and synthesized extracellular ß-1,4 endoglucanases, its activity was reduced by 10% NaCl. Based on these results, F. equiseti LPSC 1166 can be described as a halotolerant cellulolytic fungus most probably playing a key role in the decay of H. ritteriana leaf litter in "Salinas Grandes."