Improving downstream processes to recover tartaric acid, tartrate and nutrients from vinasses and formulation of inexpensive fermentative broths for xylitol production

Integrated biorefinery development using winery waste streams for the production of bacterial cellulose, succinic acid and value-added fractions

An integrated biorefinery has been developed using winery wastes (grape pomace-GP, stalks-GS, wine lees-WL). Bacterial cellulose was produced from GP extracted free sugars. Grape-seed oil and polyphenols were extracted from GP. Experimental design was employed to optimize lignin removal (50.8%) from mixtures of remaining GP solids and GS via NaOH (1.19% w/v) treatment at 70°C for 30 min. Delignification liquid contained condensed tannins with 76% Stiasny number. Enzymatic hydrolysis produced a sugar-rich hydrolysate (40.2 g/L sugars). Ethanol, antioxidants, tartaric acid and nutrient-rich hydrolysate were produced from WL. The crude hydrolysates were used in fed-batch Actinobacillus succinogenes cultures for 37.2 g/L succinic acid production. The biorefinery produces 42.65 g bacterial cellulose, 24.3 g oil, 40.3 g phenolic-rich extract with 1.41 Antioxidant Activity Index, 80.2 g ethanol, 624.8 g crude tannin extract, 20.03 g tartaric acid and 157.8 g succinic acid from 1 kg of each waste stream.

Current and future strategies for wine yeast lees valorization

Wine lees is a sludge material mainly composed of dead yeast precipitated at the bottom of wine tanks. Along with grape pomace and grape stalks, it is one of the main by-products of the winemaking industry. Given that wine lees are considered a soil pollutant, their disposal represents a cost for wineries. Numerous wine lees recovery and valorization strategies have been proposed, with a particularly steep increase in published research in recent years. This attention is strictly linked to the concepts of circular economy and environmental sustainability that are attracting the interest of the scientific community. In this review, an overview on the available wine lees recovery and valorization strategies is reported. Additionally, the methods for the extraction and valorization of yeast's cell wall polysaccharides (β-glucans and mannoproteins) are discussed. Finally, current and future innovative applications in different sectors of yeast β-glucans and mannoproteins are described and critically discussed.

Fungal biodegradation and multi-level toxicity assessment of vinasse from distillation of winemaking by-products

The wastewaters from distilleries of winemaking by-products, a scarcely studied type of vinasse, were treated by white-rot fungal strains from species Irpex lacteus, Ganoderma resinaceum, Trametes versicolor, Phlebia rufa and Bjerkandera adusta. The main objectives of this study were to evaluate fungal performance during vinasse biodegradation, their enzyme patterns and ecotoxicity evolution throughout treatment. Despite all strains were able to promote strong (>80%) dephenolization and reduction of total organic carbon (TOC), P. rufa was less affected by vinasse toxicity and exhibit better decolorization. In batch cultures at 28 °C and pH 4.0, the first phase of P. rufa biodegradation kinetics was characterized by strong metabolic activity with simultaneous depletion of TOC, phenolics and sugars. The main events of second phase are the increase of peroxidases production after the peak of laccase activity, and strong color removal. At the end of treatment, it was observed highly significant (p < 0.001) abatement of pollution parameters (83-100% removal). Since water reclamation and reuse for e.g. crop irrigation is a priority issue, vinasse ecotoxicity was assessed with bioindicators representing three different phylogenetic and trophic levels: a marine bacterium (Aliivibrio fischeri), a freshwater microcrustacean (Daphnia magna) and a dicotyledonous macrophyte (Lepidium sativum). It was observed significant (p < 0.05) reduction of initial vinasse toxicity, as evaluated by these bioindicators, deserving special mention an almost complete phytotoxicity elimination.

Optimizing the extraction process of natural antioxidants from chardonnay grape marc using microwave-assisted extraction

The aim of this work was to extract phenolic compounds from Chardonnay grape marc employing a microwave-assisted extraction (MAE). Firstly, the effect of solvent concentration (30-60%), solid mass (1.0-2.0 g) and extraction time (5-15 min) on the recovery of phenolic content and antioxidant capacity was evaluated using a response surface methodology (RSM). The optimal parameters found by RSM were 48% ethanol for the solvent content, 10 min for the extraction time, and 1.77 g for the solid mass. The extraction was carried out at room temperature to increase scaling-up opportunities at industrial level. It was found that the phenolic profile was mainly composed of flavanols, such as procyanidins, catechin and epicatechin. Furthermore, the polyphenols obtained by MAE showed a DPPH· inhibition value of 87 ± 5% and the total phenolic content was 1.21 ± 0.04 mg GAE/mL. Finally, it was observed that the degradation temperature of the extract (≈ 200 °C) was above the temperature commonly used for the manufacture of protein films by thermo-mechanical processes. This highlights the potential use of this extract as a bioactive additive in protein film forming formulations for food and pharmaceutical applications.

Potential of lees from wine, beer and cider manufacturing as a source of economic nutrients: An overview

Lees are the wastes generated during the fermentation and aging processes of different industrial activities concerning alcoholic drinks such as wine, cider and beer. They must be conveniently treated to avoid uncontrolled dumping which causes environmental problems due to their high content of phenols, pesticides, heavy metals, and considerable concentrations of nitrogen, phosphate and potassium as well as high organic content. The companies involved must seek alternative environmental and economic physicochemical and biological treatments for their revalorization consisting in the recovery or transformation of the components of the lees into high value-added compounds. After describing the composition of lees and market of wine, beer and cider industries in Spain, this work aims to review the recent applications of wine, beer and cider lees reported in literature, with special attention to the use of lees as an endless sustainable source of nutrients and the production of yeast extract by autolysis or cell disruption. Lees and/or yeast extract can be used as nutritional supplements with potential exploitation in the biotechnological industry for the production of natural compounds such as xylitol, organic acids, and biosurfactants, among others.

Recovery of squalene from wine lees using ultrasound assisted extraction-a feasibility study

The present work is a systematic approach for valorization of wine lees regarding the recovery of squalene, a bioactive lipid. Such a study is presented for the first time in literature. Separate examination of squalene content in "light" and "heavy" lees from different vinification processes by RP-HPLC demonstrated that these waste streams can be used as a source for this lipid, despite variations due to technological or genetic effects. Next, ultrasound assisted extraction of squalene from the "industrial waste" (the mixture of wine lees generated from different wines) using n-hexane was optimized with the aid of response surface methodology (independent variables: sonication duration and duty cycles). Autolysis was monitored through optical microscopy. Squalene yield (0.6 ± 0.08 g SQ/kg dry lees) was comparable to that of recently examined potential sources (0.2-0.35 g SQ/kg dry olive pomace and 0.06 g SQ/kg olive leaves).

Valorization of winery waste vs. the costs of not recycling

Wine production generates huge amounts of waste. Before the 1990s, the most economical option for waste removal was the payment of a disposal fee usually being of around 3000 Euros. However, in recent years the disposal fee and fines for unauthorized discharges have increased considerably, often reaching 30,000-40,000 Euros, and a prison sentence is sometimes also imposed. Some environmental friendly technologies have been proposed for the valorization of winery waste products. Fermentation of grape marc, trimming vine shoot or vinification lees has been reported to produce lactic acid, biosurfactants, xylitol, ethanol and other compounds. Furthermore, grape marc and seeds are rich in phenolic compounds, which have antioxidants properties, and vinasse contains tartaric acid that can be extracted and commercialized. Companies must therefore invest in new technologies to decrease the impact of agro-industrial residues on the environment and to establish new processes that will provide additional sources of income.