Grape pomace (GP) is a low-value by-product that contains a significant amount of high value-added products. The huge amount of non-edible residues of GP wastes (seeds, skins, leaves and, stems) produced by wine industries causes’ environmental pollution, management issues as well as economic loss. Studies over the past 15–20 years revealed that GP could serve as a potential source for valuable bioactive compounds like antioxidants, bioactive, nutraceuticals, single-cell protein, and volatile organic compounds with an increasing scientific interest in their beneficial effects on human and animal health. However, the selection of appropriate techniques for the extraction of these compounds without compromising the stability of the extracted products is still a challenging task for the researcher. Based on the current scenario, the review mainly summarizes the novel applications of winery wastes in many sectors such as agriculture, pharmaceuticals, cosmetics, livestock fields, and also the bio-energy recovery system. We also summarize the existing information/knowledge on several green technologies for the recovery of value-added by-products. For the promotion of many emerging technologies, the entrepreneur should be aware of the opportunities/techniques for the development of high-quality value-added products. Thus, this review presents systematic information on value-added by-products that are used for societal benefits concerning the potential for human health and a sustainable environment.

Large quantities of waste biomass are generated annually worldwide by many industries and are vastly underutilized. However, these wastes contain sugars and other dissolved organic matter and therefore can be exploited to produce microbial biopolymers. In this study, four selected Halomonas strains, namely, Halomonas caseinilytica K1, Halomonas elongata K4, Halomonas smyrnensis S3, and Halomonas halophila S4, were investigated for the production of exopolysaccharides (EPS) using low-cost agro-industrial wastes as the sole carbon source: cheese whey, grape pomace, and glycerol. Interestingly, both yield and monosaccharide composition of EPS were affected by the carbon source. Glucose, mannose, galactose, and rhamnose were the predominant monomers, but their relative molar ratio was different. Similarly, the average molecular weight of the synthesized EPS was affected, ranging from 54.5 to 4480 kDa. The highest EPS concentration (446 mg/L) was obtained for H. caseinilytica K1 grown on cheese whey that produced an EPS composed mostly of galactose, rhamnose, glucose, and mannose, with lower contents of galacturonic acid, ribose, and arabinose and with a molecular weight of 54.5 kDa. Henceforth, the ability of Halomonas strains to use cost-effective substrates, especially cheese whey, is a promising approach for the production of EPS with distinct physicochemical properties suitable for various applications.

A bioadsorbent formulated with a secondary raw material, consisting of grape marc, subjected to a bioxidize process and entrapped in calcium alginate beads, was used for the desalination of water containing copper(II) sulfate. Experiments were established under different experimental conditions varying the concentration of contaminant, the amount of bioadsorbent, and the extraction time through response surface methodology. The most significant variable in the removal of copper(II) sulfate was the amount of bioadsorbent employed, followed by the extraction time; whereas, the adsorbent capacity was more influenced by the amount of contaminant and the amount of bioadsorbent used. At the highest concentration of copper(II) sulfate (0.15 mol/L), the equations obtained predict that the bioadsorbent has a capacity of 2785 mg/g and produces a copper(II) removal about 43% using low adsorbent/water ratios, 1:10 (v/v), and maximum extraction times; whereas, it would remove 97.2% of copper(II) sulfate in 5 min, using adsorbent/water ratios close to 1:2 (v/v), with capacity values, in this case, around 1800 mg/g. The encapsulation of the bioxidize adsorbent increased its capacity to 30% and allowed the precipitation of sulfate ions as calcium sulfate. The results obtained in this work could presume advances for promoting the industrial symbiosis between winery and environmental industries. Graphical abstract Utilization of secondary raw material, consisting of bioxidize grape marc from winery industry, as bioadsorbent encapsulated in calcium alginate beads, for the removal of copper(II) sulfate from water

A real industrial effluent from the pre-treatment and painting processes was polished through adsorption using alternative biochar derived from grape pomace wastes. The biochar was produced in a pilot-scale plant from composted grape pomace. Biochar showed an equilibrium between acidic and basic groups on the surface. The presence of irregular cavities in the structure and mesopores was confirmed by analyzing N₂ physisorption and SEM. Concerning the effluent, Ni and Zn were the main problematic elements. The adsorption isotherms and kinetics of Ni and Zn from the effluent using the biochar could be represented by the Henry, pseudo-first-order, and pseudo-second-order models, respectively. Adsorption equilibrium was reached within 60 min for Ni and Zn present in the real effluent. Besides, the adsorption process was endothermic, favorable, and spontaneous. These results demonstrate that Zn and Ni metals were successfully removed from the industrial effluent, presenting final concentration values within the limit of legislation for effluent disposal in agricultural soil.

In this work, an aqueous solution containing industrial dyes consisting of methylene blue (MB), and methyl red (MR) was treated with bio-oxidize grape marc entrapped or not in calcium alginate hydrogels. Experiments were carried out in batch, a room temperature using different concentration of adsorbents and dyes. When dyes were evaluated separately, non-immobilized grape marc hydrogel was unable to remove any MR, whereas when the bioadsorbent was immobilized in calcium alginate beads the removal of MR was around 88%. Contrarily, 98% of MB was removed with both, non-entrapped or entrapped grape marc. Regarding binary mixtures, it was observed that the adsorption of MR was not affected by the presence of MB, whereas the adsorption of MB decreased in high extend on non-entrapped grape marc when MR was present.Adsorption conditions were optimized for binary mixtures using a Box-Behnken factorial design, obtaining theoretical equations that allowed to calculate the removal percentage and capacity of calcium alginate-grape marc hydrogel depending on the concentration of dyes (40–100 mg/L), ratio between bioadsorbent and water stream (0.6–1.2) and adsorption time (10–60 min). The equations obtained revealed that grape marc hydrogel is able to remove 100.0–93.3% of MB and 78.72–57.80% of MR in 10 min in the range of dye and bioadsorbent stablished in the experimental design, being the extraction time the less significant variable. Additionally, the kinetic study showed that pseudo-second-order was the model that better explained the bioadsorption process for both dyes in binary mixtures onto grape marc hydrogel.

Biochar is a product of the thermal decomposition of biomass under a limited supply of oxygen and can be deriving from pyrolysis or gasification. As the product is rich in highly recalcitrant carbon, it has been proposed as a soil amendment to improve soil fertility and to stock carbon in soils. However, the contaminant compounds present in biochar could represent potential environmental threats. The gasification biochar is a promising by-product, but its effects on soil microarthropods are still nearly unknown. The aim of this study was to assess, using a prognosis approach, any ecotoxicological consequences of four biochars (conifer, poplar, grape marc, and wheat straw) on the springtail Folsomia candida. This was assessed through a series of tests: an avoidance behavior test, a survival and reproduction test, and a test based on the hatching of eggs. Biochars were tested at different concentrations (pulverized and diluted w/w with an artificial standard soil). The results showed that the springtails did not tend to avoid the biochars’ substrates up to the rate of 2–5%, but any higher levels of concentration caused the animals to keep away from it. While mortality was negatively affected only in the grape marc biochar, reproduction was significantly reduced in all biochars considered. The hatching of the eggs was anticipated at even the lowest concentrations of herbaceous biochars, while a severe delay was observed in both concentrations tested of the conifer biochar. The endpoints considered were negatively affected by pH, polycyclic aromatic hydrocarbons, and heavy metals (in order of importance). The findings confirmed the potential adverse effects that gasification biochars could have on soil microarthropods and demonstrated the necessity of introducing these tests into biochar characterization protocols.

In this research, the production of exo-pectinase by Bacillus pumilus using different agricultural wastes was studied. Agricultural wastes containing pectin such as wheat bran, sugar beet pulp, sunflower plate, orange peel, banana peel, apple pomace and grape pomace were tested as substrates, and activity of exo-pectinase was determined only in the mediums containing sugar beet pulp and wheat bran. Then, effects of parameters such as concentrations of solid substrate (wheat bran and sugar beet pulp) (A), ammonium sulphate (B) and yeast extract (C) on the production of exo-pectinase were investigated by response surface methodology. First, wheat bran was used as solid substrate, and it was determined that exo-pectinase activity increased when relatively low concentrations of ammonium sulphate (0.12–0.21 % w/v) and yeast extract (0.12–0.3 % w/v) and relatively high wheat bran (~5–6 % w/v) were used. Then, exo-pectinase production was optimized by response surface methodology using sugar beet pulp as a solid substrate. In comparison to P values of the coefficients, values of not greater than 0.05 of A and B²showed that the effect of these process variables in exo-pectinase production was important and that changes done in these variables will alter the enzyme activity.

Vermicomposting is a process by which earthworms together with microorganisms degrade organic wastes into a humus-like material called vermicompost. This process does not include a thermophilic stage, and therefore, the possible presence of pathogens represents a potential health hazard. To elucidate the effect of earthworms in the selective reduction of pathogens, grape marc substrate was artificially inoculated with Escherichia coli, Enterococcus spp., thermotolerant coliform bacteria (TCB), and Salmonella spp., and their reduction during vermicomposting was monitored. Various defense mechanisms eliminating microorganisms in the earthworm gut were assumed to be involved in the process of pathogen reduction. Therefore, we followed the expression of three pattern recognition receptors (coelomic cytolytic factor (CCF), lipopolysaccharide-binding protein (LBP), and Toll-like receptor (v-TLR)), two antimicrobial molecules (fetidin/lysenins and lysozyme), and heat shock protein HSP70. We detected the significant decrease of some defense molecules (fetidin/lysenins and LBP) in all pathogen-inoculated substrates, and the increase of CCF and LBP in the Salmonella spp.-inoculated substrate. At the same time, the reduction of pathogens during vermicomposting was assessed. We observed the accelerated reduction of E. coli, Enterococcus spp., and TCB in pathogen-inoculated substrates with earthworms compared to that without earthworms. Moreover, the differences between the microbiome of grape marc substrate and earthworm intestines were determined by high throughput sequencing. This analysis revealed that the bacterial composition of grape marc substrate differed from the composition of the content of earthworm intestines, suggesting the elimination of specific bacterial species during food passage through the gut.