Recycling and valorization of distilled grape marc through vermicomposting: a pilot-scale study

Abstract

The present study sought to evaluate the effectiveness of vermicomposting for the valorization of distilled grape marc, one of the main solid by-products of the winery sector during a 56-day pilot-scale trial. The increase in the density and biomass of earthworms (Eisenia andrei) during the earlier stages of the process reflected the suitability of the distilled marc (Vitis vinifera L. cv. Mencía) as feedstock in order to sustain large earthworm populations on a pilot-scale level. Supporting this, from 14 days onwards the pH of Mencía distilled marc fell within weak-alkaline levels and the electrical conductivity was between 0.21 and 0.11 mS cm−2 providing optimum conditions for earthworm growth. A rapid decrease in microbial activity as well as in the content of total polyphenols, both indicative of stabilized materials was also recorded after 14 days of vermicomposting. Moreover, the content of macro- and micronutrients in the end product matched with those considered to have the quality criteria of a good vermicompost with respect to plant health and safe agricultural use. Altogether, it underlines the feasibility of vermicomposting as an environment-friendly approach for the biological stabilization of distilled grape marc fulfilling both environmental protection and fertilizer production.

Effect of Biochar on Vermicompost Production: Chemical, Biochemical, and Biological Properties

“…Our findings indicate that the BC treatments have either equivalent or lower enzyme activity than the vermicompost control (refer to Table 4). High enzymatic activity is common at the beginning of the vermicomposting process [43] due to the action of microbes in the presence of earthworms [8]. Consequently, an elevated level of enzyme activity could suggest that the vermicompost is not yet fully mature.…”

“…Biochars of wheat and maize straw are recognized as rich carbon additives that facilitate carbohydrate metabolism [57] by breaking down cellulose and hemicellulose. However, as maturation progresses, these processes decrease in intensity due to the reduced availability of new material [8]. Therefore, it was expected that when assessed with these indicators, the treatments would score lower than the reference, with the exception of T 4 (vermicompost + carbonaceous material from poultry litter).…”

“…Moreover, vermicompost derived from grape bagasse has been found to possess adsorption capabilities, making it effective in removing pharmacological substances from water solutions [7]. The use of grape bagasse for vermicomposting offers not only a sustainable waste management solution for the wine industry but also a pathway for producing a valuable organic fertilizer to enhance soil fertility and plant growth [8]. Overall, the vermicomposting of grape bagasse presents a promising approach for producing high-quality vermicompost and for the sustainable management of organic waste.…”

Nature‐based strategies to regenerate the functioning and biodiversity of vineyards

“…Anaerobic digestates could be applied to agricultural soils and might be used in both their solid and liquid phases, depending on their characteristics (Slepetiene et al, 2023). Vermicomposting (organic matter transformation by earthworms) is another viable biotechnology for the treatment of wine organic wastes, as demonstrated by several studies (Gómez‐Brandón et al, 2021, 2023; Karapantzou et al, 2023; Paradelo et al, 2011). Thus, the potential valorisation of by‐products generated during wine production enables the recycling of organic matter and nutrients, fostering sustainable viticulture within a circular economy framework.…”