The microwave assisted hydrolysis of urban biowaste fermented material to added value soluble lignin-like substances occurs with similar yields as, but in much shorter time than by, conventional heating.

Soluble biobased lignin‐like polymeric substances (SBO) isolated from the alkaline hydrolysates of composted biowastes are promising chemical auxiliaries for multiple uses. They have good surfactant properties. Their black color spoils their performance in detergency and dyeing. Ozonization of SBO is reported now to yield bleached biosurfactants with improved performance. The work was performed, with SBO obtained from composted gardening residues, alone or mixed with kitchen wastes. They were dissolved in water at 3.3 % concentration. Oxygen containing 4 mol/mol % ozone was flown at 60 L h−1 for 48 h through the SBO solution. The crude ozonized products in ca. 80 % yield were filtered through different molecular cut off membranes and characterized for chemical features, molecular weight, and surface tension in water. The ozonized fractions with 200–500 kDa molecular weights accounted for 12–29 % of the total ozonized fractions's organic matter. They lowered water surface tension to 48–52 mN m−1. The lower molecular weight ozonized fractions had no surfactant activity, but their molecular features suggest other potentially valuable uses.

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.