Danilo De Faveri

Vanillin production by recombinant strains of Escherichia coli

Vanillin production from ferulate was studied using different recombinant strains of Escherichia coli. To prevent the occurrence of aerobic conditions and then possible product oxidation, tests were performed in Erlenmeyer flasks under mild mixing (150 rpm). Among other transformants, E. coli JM109(pBB1) appeared to be the best vanillin producer, being able to convert no less than 95% of starting ferulate to the product within 1h. This yield decreased down to 72% after 72h, likely because of a non-specific oxidase activity responsible for vanillin oxidation to vanillate.

An Assessment on Xylitol Recovery Methods

The interest in dietary sugars and polyols has increased considerably in recent years, as they are candidates for many commercial applications in different sectors like food and pharmaceutical industries. This chapter aimed at providing an overview on the xylitol recovery using different approaches. After a brief description of the applications of such an important polyol component in the food and medicine industries along with its physicochemical properties, the traditional ways of providing xylitol, specifically the chemical synthesis, are described and compared with the new biotechnological options. Emphasis has been addressed on the present literature on xylitol recovery assessment, specifically focusing on xylitol recovery by crystallization. The effects of the most influencing factors such as pretreatment, initial xylitol super saturation value, crystallization temperature as well as solvent on xylitol recovery were discussed. The chapter points out that even if in the last few years xylitol crystallization has drawn more attention, important research efforts are still required to develop downstream technologies able to economically recover this compound in a very pure form, suitable for commercial purposes.