ORIGINAL PAPER Dextransucrase Stability in Cashew Apple Juice Talita L. Honorato & Sueli Rodrigues Received: 8 November 2007 / Accepted: 3 January 2008 / Published online: 29 January 2008 # Springer Science + Business Media, LLC 2008 Abstract The use of agriculture waste as substrate for biotechnological process became an interesting alternative to reduce production costs and the negative impact of agricultural wastes disposal in the environment. In Brazil, cashew tree cultivation is done aiming the cashew nut production, and tons of cashew apples are wasted in the field after the nut removal. Thus, cashew apple juice can be used as low cost substrate for biotechnological process. In this study, the stability of dextransucrase produced in a fermentation medium using cashew apple juice as substrate was evaluated. The crude enzyme was stable at 30 °C for 30 h at pH ranging from 4.5 to 5.5. The partially purified enzyme was stable in non-fermented cashew apple juice at pH 5.0 for 96 h at 30 °C. The high stability of the enzyme in cashew apple juice at room temperature allows its industrial use without needing the enzyme purification, consequently reducing process costs. Keywords Agriculture substrates . Enzyme stability . Glycosyltransferase . Fermentation Introduction Alternative substrates have been studied as low-cost substrates for microbial fermentation to produce several products for chemical, petrochemical, pharmaceutical, and food industry (Lacaze et al. 2007; Vazquez et al. 2006; Angumeenal and Venkappaya 2005; Tony et al. 2004; Adham 2002; Kuerbanoglu 2004; Kumasr et al. 2003; Hang and Woodams 2000; El-Samragy et al. 1996; Stredanska et al. 1993). Agriculture residues and wastes are the most suitable low- cost substrates for microbial cultivation. Cashew apple is the peduncle of the cashew fruit, which is rich in reducing sugars (fructose and glucose), vitamins, minerals, and some amino acids (Campos et al. 2004; Oliveira et al. 2002). The cashew tree grows even on poor soils with low rainfall and is cultivated in 32 countries around the world, with Brazil, India, Vietnam, and Nigeria as the main producers. Although cashew apples can be consumed as juice, as ice cream, and as other foodstuffs, the cashew tree cultivation in Brazil is an agriculture activity that aims mainly to produce cashew nuts. The nuts represent only 10% of the total fruit weight, and large amounts of cashew apples are left in the field after the removal of the nut (Honorato et al. 2007). According to official data, the Brazilian Northeast presents an annual production of approximately 2 millions of tons of cashew apples, and 90% of this production is lost or under- utilized. As such, the cashew apple is considered an agriculture waste, and its nutritive juice can be a suitable low-cost substrate for oligosaccharide synthesis by the acceptor re- action, as this juice is rich in glucose and fructose (acceptors). Glycosyltransferases are enzymes that catalyze the transfer of glycosyl residues from a donor molecule to a particular acceptor. Lactic acid bacteria produce a wide variety of a particular group of glycosyltransferases, which Food Bioprocess Technol (2010) 3:105–110 DOI 10.1007/s11947-008-0053-2 T. L. Honorato Departamento de Processos Químicos, Universidade Estadual de Campinas, Faculdade de Engenharia Química, Barão Geraldo, Caixa Postal 6066, CEP 13083-970 Campinas, SP, Brazil S. Rodrigues (*) Departamento de Tecnologia de Alimentos, Universidade Federal do Ceara, Av. Mister Hull, 2977, Bloco 858, Campus do Pici, CEP 60356-000 Fortaleza, CE, Brazil e-mail: sueli@ufc.br