Biochar production from the pyrolysis of food waste: Characterization and implications for its use

Food waste (FW) represents a large group of wastes that impose several issues on their management, especially in terms of microbiological and leaching pollution, and greenhouse gas emissions. According to the EU circular economy vision, finding a new way for FW valorisation to obtain reusable materials or compounds represents a priority. Thermal treatment represents one of the suitable ways for FW processing, and pyrolysis in particular presents many advantages in producing solid carbonaceous biochar, reusable oil and gas. This paper analyses biochar that was produced via thermal pyrolysis of FW. The influence of an organic additive (wooden sawdust) and a catalyst (zeolite) on the pyrolytic process at 600 °C was investigated. The results highlight how the initial composition of the feedstock (FS) influenced the characteristics of the obtained biochar. The addition of organic additives and catalyst did not change significantly the Brunauer–Emmett–Teller surface area and the calorific value. For all the analysed parameters, all tested FS respected the guidelines proposed by International Biochar Initiative (IBI) and the European Biochar Certificate (EBC) for possible reuse in agriculture and urban areas. The results suggest that biochar from FW could be potentially used in agriculture and urban green infrastructure, but the authors suggest further studies, especially on the effect of high electrical conductivity due to the typical high concentration of salts in FW

Purification and characterization of two forms of endo-beta-1,4-mannanase from a thermotolerant fungus, Aspergillus fumigatus IMI 385708 (formerly Thermomyces lanuginosus IMI 158749)

Two extracellular endo-β-1,4-mannanases, MAN I (major form) and MAN II (minor form), were purified to electrophoretic homogeneity from a locust bean gum-spent culture fluid of Aspergillus fumigatus IMI 385708 (formerly Thermomyces lanuginosus IMI 158749). Molecular weights of MAN I and MAN II estimated by SDS-PAGE were 60 and 63 kDa, respectively. IEF afforded several glycoprotein bands with pI values in the range of 4.9–5.2 for MAN I and 4.75–4.9 for MAN II, each exhibiting enzyme activity. MAN I as well as MAN II showed highest activity at pH 4.5 and 60 °C and were stable in the pH range 4.5–8.5 and up to 55 °C. In accordance with the ability of the enzymes to catalyze transglycosylation reactions, 1H NMR spectroscopy of reaction products generated from mannopentaitol confirmed the retaining character of both enzymes. Both MAN I and MAN II exhibited essentially identical kinetic parameters for polysaccharides and a similar hydrolysis pattern of various oligomeric and polymeric substrates. Both β-mannanases contained identical internal amino acid sequence corresponding to glycoside hydrolase family 5 and also a cellulose-binding module. These data suggested that both MAN I and MAN II are products of the same gene differing in posttranslational modification. Indeed, the corresponding gene was identified within the recently sequenced Aspergillus fumigatus genome (http://www.sanger.ac.uk/Projects/A_fumigatus/)