1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 z Sustainable Chemistry Mild Hydrogenation of Urban Biowaste Hydrolysates to Biopolymers with Improved Properties. Enzo Montoneri,* [a] Gloria Fabbri, [a] Giorgio Grillo, [b] Silvia Tabasso, [b] Giancarlo Cravotto, [b] Pierluigi Quagliotto, [c] Andrea Baglieri, [d] Valter Boero, [a] and Michèle Negre [a] This work reports the hydrogenation of soluble biopolymers (SBP) obtained by hydrolysis of municipal biowaste anaerobic digestate (D) and compost (CP). The SBP are mix of hetero- genous molecules with 5–750 kDa molecular weight constitued by aliphatic and aromatic C moieties substitued by acid and basic functional groups. They are mutipurpose products for use in the chemical industry as biosurfactants and plastics’ additives, in agriculture and in animal husbandry. Purpose of hydrogenation was to improve SBP properties, while keeping macromolecularity. Hydrogenation was carried out in 4–5% water solution at pH 10 at 100 °C and 35 bar H 2 pressure for 2– 30 min. Results show hydrogenation of up to 35% SBP C to products containing more aliphatic C and different molecular weight distribution. Relative to pristine SBP, the molecular weight of hydrogenated CP SBP and of D SBP are, respectively, higher and lower. Surfactants properties improve upon hydro- genation. Hydrogenated D SBP are better surfactants than hydrogenated CP SBP. Further improvement and uses of hydrogenated SBP are discussed. Introduction There are two major societal concerns nowadays. One is the depletion of fossil source as feedstock to produce fuels and chemicals. The other is the increasing production of wastes. Both have negative environmental impacts. One approach to alleviate both problems is using biowastes as renewable feedstock alternative to fossil sources. In this context, since 2004, the authors of the present work have carried R&D work focused on municipal biowastes (MBW). The reason for choosing MBW, and not biowaste from other sources, is that MBW is the only negative [1] cost feedstock, worldwide easily available in every urban settlement. [2] Over this time, the authors have developed a chemical hydrolysis process convert- ing MBW to soluble biopolymers (SBP). They have demon- strated the performance of SPB as multipurpose products for use in the chemical industry as biosurfactants and for the manufacture of composite plastic materials, in agriculture as soil fertilizers and plant bio stimulants, and in animal husban- dry as diet supplement. [3] Currently, biowastes are processed by fermentation, incin- eration or pyrolysis. [4,5] These disrupt the polymeric structures of the native organic matter (NOM). They produce simple molecules to use as biofuel or as building blocks for the manufacture of chemical commodities and specialities. On the contrary, the above MBW hydrolysis process yields high molecular weight fragments in the range of 5 to over 750 kDa. These save the memory of the polymeric nature and function- alities of NOM, which allow the multipurpose properties of SBP. In the authors concept, the SBP represent also a potential intermediate feedstock to produce advanced bio-based chem- ical specialities and materials by applying organic chemistry reactions. Organic chemistry is the base technology of oil refineries. These produce unsaturated hydrocarbons and aromatic mole- cules from which most commercial commodities and special- ities are obtained by chemical reactions such as oxidation, hydrogenation, alkylation, halogenation, and polymerization. In principle, this approach represents a model strategy to follow also for the valorization of MBW as feedstock. However, MBW, as well as SBP, presents a major challenging criticality. Contrary to simple organic molecules having a definite well known chemical structure, MBW or SBP are complex mixes of molecules differing for chemical composition and molecular weight. Thus, both the reaction conditions and the character- ization of the products require much research work before understanding whether they can compete for cost and performance with fossils’ processes and products. The authors have already faced the challenges connected with the complexity of MBW and SBP chemical composition in previous work on the chemical hydrolysis [6] of MBW and chemical oxidation of SBP. [7] They have reported the following results. The hydrolysis of MBW yields a range of molecules with 5–750 kDa constituted by aliphatic and aromatic carbon C [a] Prof.E.Montoneri,G.Fabbri,Prof.V.Boero,Prof.M.Negre Università di Torino, Dipartimento di Scienze Agrarie, Forestali e Alimentari, Largo P. Braccini 2, 10095 Grugliasco (TO), Italy E-mail: enzo.montoneri@gmail.com [b] G. Grillo, Dr. S. Tabasso, Prof. G. Cravotto Università di Torino, Dipartimento di Scienza e Tecnologia del Farm- aco,Via P. Giuria 9, 10125 Torino, Italy [c] Dr. P. Quagliotto Università di Torino, Dipartimento di Chimica, Via Giuria 7, 10125 Torino, Italy [d] Prof. A. Baglieri Università di Catania, Dipartimento di Scienze delle Produzioni Agrarie e Alimentari, Via S. Sofia 98, 95123 Catania, Italy Supporting information for this article is available on the WWW under https://doi.org/10.1002/slct.201900805 Full Papers DOI: 10.1002/slct.201900805 4168 ChemistrySelect 2019, 4,4168–4177 © 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim