Processed vs. Non-Processed Biowastes for Agriculture: Effects of Post-Harvest Tomato Plants and Biochar on Radish Growth, Chlorophyll Content and Protein Production

Abstract

The aim of this work was to address the issue of processed vs. non-processed biowastes for agriculture, by comparing materials widely differing for the amount of process energy consumption. Thus, residual post harvest tomato plants (TP), the TP hydrolysates obtained at pH 13 and 60 °C, and two known biochar products obtained by 650 °C pyrolysis were prepared. All products were characterized and used in a cultivation of radish plants. The chemical composition and molecular nature of the materials was investigated by solid state 13C NMR spectrometry, elemental analysis and potentiometric titration. The plants were analysed for growth and content of chlorophyll, carotenoids and soluble proteins. The results show that the TP and the alkaline hydrolysates contain lignin, hemicellulose, protein, peptide and/or amino acids moieties, and several mineral elements. The biochar samples contain also similar mineral elements, but the organic fraction is characterized mainly by fused aromatic rings. All materials had a positive effect on radish growth, mainly on the diameter of roots. The best performances in terms of plant growth were given by miscanthus originated biochar and TP. The most significant effect was the enhancement of soluble protein content in the plants treated with the lowest energy consumption non processed TP. The significance of these findings for agriculture and the environment is discussed.

Pre-treatment and extraction techniques for recovery of added value compounds from wastes throughout the agri-food chain

“…At the current state of technology, the most feasible and rewarding applications of the above SSP and SLP seem to be in agriculture and anaerobic digestion. Added to cultivation soil, the SLP has been found to significantly increase growth and productivity of several plants, i.e., tomato and red pepper, 282 corn, 283 beans, 284 radish, 285 and ornamental plants. 286 They have also been proven to be efficient plant disease suppressants.…”

“…The SBO could find use in the diversified field 276 of the chemical industry, plastic manufacture 279,287,288 and agriculture. [282][283][284][285]292 Estimates on operating costs and how feasible the implementation of the proposed processes and products at commercial production and use level are reported for the hydrolysis of municipal biowaste compost carried out by conventional and microwave heating 278 and for some case study applications of the SLP as active principles for agriculture, 286 auxiliaries for ecofriendly biowaste anaerobic fermentation, 290,291 and components for the manufacture of biobased blend plastic articles. 279,287,288 All these estimates confirm that the conversion of the composted municipal biowaste organic matter to SLP can yield revenue from SLP sales in the chemical and agriculture market, which are several order of magnitudes higher than the revenue obtained by the sale of the pristine compost.…”

Thermopressed Binderless Fiberboards from Post-HarvestTomato and Maize Plants

“…In the last twelve years, several papers have been published on the valorization of biowastes from municipal [1] and agriculture [2] sources as feedstock for the production of multipurpose speciality chemicals to be used in the chemical industry, agriculture and animal husbandry, for environmental remediation, and for the manufacture of materials. The wide range of applications arises from the fact that these chemicals are constituted by mixes of biopolymers (BPs) with molecular weight ranging from 5 to several hundred kDa [3].…”

“…These bio-based compounds, blended with synthetic polyethylene copolymers, yield plastic films that can be used for soil protection in agriculture. Finally, the raw PHT plants and their low temperature alkaline hydrolysates have been shown efficient biostimulants for the cultivation of bean [12] and radish [2] plants. In the present work, the manufacture of self-bonded wood-fiber based boards from post-harvest tomato and maize plant materials was investigated as further attractive application, which could broaden the range of opportunities to valorize the above agriculture residues.…”

“…In this sector, as well as in all sectors of human activities, the use and/or the re-use of recycled materials and renewable materials is a currently pursued strategy for reducing the implied energy consumption and environmental impact [15]. In order to manufacture the boards described in this work, the PHT, PHM and CPHT were available from previous works [2,4,5,12]. The PHT and PHM were the plants collected at the end of the crop production stage of the tomato and maize experimental cultivation trials, respectively.…”