Potential of native and bioprocessed brewers' spent grains as organic soil amendments

Abstract

IntroductionThe use of novel soil amendments and the exploitation of plant growth-promoting microorganisms are considered promising tools for developing a more sustainable agriculture in times when ensuring high-yield productions with limited resources is essential.MethodsIn this study, the potential of brewers' spent grain (BSG), the major by-product of the brewing industry, as organic soil amendment, was investigated. Bioprocessed BSG, obtained by an enzymatic treatment coupled with fermentation, together with native BSG, were used as amendments in a pot-trial. An integrated analytical approach aimed at assessing the modification of the physicochemical properties of a typical Mediterranean alkaline agricultural soil, and the plant growth-promoting effect on escarole (Cichorium endivia var. Cuartana), was carried out.ResultsThe use of biomasses led to soil organic content and total nitrogen content up to 72 and 42% higher, compared to the unamended soils. Moreover, the lower pH and the higher organic acids content doubled phosphorus availability. Although the number of leaves per plant in escaroles from pots amended with native and bioprocessed BSG did not show any difference compared to plants cultivated on unamended pots, the average fresh weight per escarole head, was higher in pots amended with bioprocessed BSG.DiscussionHence, the results collected so far encourage BSG application for agricultural purpose, while solving the problem of disposing of such abundant side stream.

The potential use of brewers' spent grain-based substrates as horticultural bio-fertilizers

“…In particular, these kind of bio-fertilizers enhance soil fertility, improving aggregation, hydraulic conductivity, total porosity, and cation exchange capacity (CEC) (Singh et al, 2022), supplying a wide range of nutrients (N, P, K, Ca, Mg, etc.) (Cacace et al, 2022;Walia and Kaur, 2024). Moreover, previous studies (Budroni et al, 2020;Bianco et al, 2022Bianco et al, , 2024 have highlighted that processed BSG (i.e., compost and vermicompost) are rich in microbial consortia including lactic acid bacteria (Weissella, Pediococcus), plant growth-promoting bacteria (Bacillus, Pseudomonas, Pseudoxhantomonas), biostimulant yeasts (Pichia fermentans), and fungi (Trichoderma reesei, Beauveria bassiana), which can improve soil fertility, enhance resistance to abiotic and biotic stressors, and act against fungi and insect pests.…”

Enhancing Fertilizer Effect of Bioprocessed Brewers’ Spent Grain by Microbial Consortium Addition

“…These microbial groups have been considered among plant growth-promoting microorganisms (PGPM). Particularly, LAB can regulate phosphate in soil, fix atmospheric nitrogen, act as biocontrol agents, and increase the shelf life of the amendment [40]. Yeasts have been described as antagonists of various plant pathogens and are currently considered for biocontrol applications [41].…”