MINI-REVIEW Enzyme oxidation of plant galactomannans yielding biomaterials with novel properties and applications, including as delivery systems Yves M. Galante 1 & Luca Merlini 1 & Tiziana Silvetti 2 & Paola Campia 2 & Bianca Rossi 3,4 & Fiorenza Viani 3 & Milena Brasca 2 Received: 6 March 2018 /Revised: 12 April 2018 /Accepted: 14 April 2018 # Springer-Verlag GmbH Germany, part of Springer Nature 2018 Abstract New biomaterials from renewable sources and the development of Bfunctionalized biopolymers^ are fields of growing industrial interest. Plant polysaccharides represent a valid alternative to traditional synthetic polymers, which are obtained from monomers of fossil, non-renewable origin. Several polysaccharides, either in their natural or chemically/biochemically modified forms, are currently employed in the biomedical, food and feed, and industrial fields, including packaging. Sustainable biochemical reactions, such as enzyme modifications of polysaccharides, open further possibilities for new product and process innovation. In the present review, we summarize the recent progress on enzyme oxidation of galactomannans (GM) from few leguminous plants (performed either with galactose oxidase or laccase) and we focus on the versatile and easily accessible laccase/TEMPO oxidative reaction. The latter causes a steep viscosity increase of GM water solutions and a transition of the gels from a viscous to an elastic form, due to formation of emiacetalic bonds and thus of internal cross-linking of the polymers. Following lyophilization of these hydrogels, stable aerogels can be obtained, which were shown to have good potential as delivery systems (DS) of actives. The active molecules tested and herewith described are polymyxin B, an antibiotic; nisin, an antimicrobial peptide; the enzymes lysozyme, protease and lipase; the mixture of the industrial microbiocides 5-chloro-2-methyl-4-isothiazolin-3-one (CIT) and 2-methyl-4-isothiazolin-3-one (MIT). The ad- vantages of such aerogel systems and the possibilities they open for future developments, including as DS, are described. Keywords Galactomannans . Enzyme oxidation . Aerogels . Delivery system . Antimicrobial General introduction: polysaccharides and galactomannans Plant polysaccharides are natural polymers from renewable sources and of non-fossil origin, which can often represent a valid and sustainable alternative to more traditional chemical polymers, produced from oil-derived monomers, such as polyesters, polyacrylates, and polyurethanes. In their natural, chemically and/or biochemically modified forms, polysaccharides conform to a large extent with the * Yves M. Galante yves.galante@icrm.cnr.it Luca Merlini luca.merlini@icrm.cnr.it Tiziana Silvetti tiziana.silvetti@ispa.cnr.it Paola Campia liberpa@gmail.com Bianca Rossi bianca.rossi@polimi.it Fiorenza Viani fiorenza.viani@polimi.it Milena Brasca milena.brasca@ispa.cnr.it 1 Istituto di Chimica del Riconoscimento Molecolare (ICRM), C.N.R, Via Mario Bianco 9, 20131 Milan, Italy 2 Istituto di Scienze delle Produzioni Alimentari (ISPA), C.N.R, Via Celoria 2, 20133 Milan, Italy 3 Istituto di Chimica del Riconoscimento Molecolare, C.N.R, Via Mancinelli 7, 20131 Milan, Italy 4 Present address: Department of Chemistry, Materials, and Chemical Engineering BG. Natta^, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milan, Italy Applied Microbiology and Biotechnology https://doi.org/10.1007/s00253-018-9028-z