Enzyme behaviour in non-conventional systems

Most important recent advances in biocatalytic biphasic systems such as aqueous two-phase reactor systems using environmental sensitive polymers, two-phase aqueous-organic systems, reverse micelles, microemulsion-based organogels, and trapped aqueous-organic solvent continuous biphasic reactors are reviewed.Centro de Investigación y Desarrollo en Fermentaciones Industriale

Enzyme Behaviour in Non-conventional Systems

356-361Most important recent advances in biocatalytic biphasic systems such as aqueous two-phase reactor systems using environmental sensitive polymers, two-phase aqueous-organic systems, reverse micelles, microemulsion-based organogels, and trapped aqueous-organic solvent continuous biphasic reactor are reviewed

Catalytic Properties of Lipase Extracts from Aspergillus niger

Ispitivanjem lipolitičkih sojeva metodom uzgoja na podlozi s dodatkom rodamina B i maslinova ulja odabran je soj plijesni Aspergillus niger MYA 135. Proizvodnja lipaze submerznim postupkom u podlozi s dodatkom 2 % maslinova ulja poboljšana je za više od 50 % s obzirom na osnovne uvjete uzgoja. Optimalni katalitički uvjeti za proizvodnju lipaze uz dodatak maslinova ulja bili su pH=6,5 i temperatura od 30 do 35 °C. Pri proizvodnji ekstrakta lipaze u osnovnim uvjetima te su se vrijednosti približavale kiselom mediju (4,5 i 6,5) i temperaturi od 35 do 37 °C. Uočena je neznatna promjena aktivnosti lipaze s promjenom pH vrijednosti. Predinkubacijom pri 37 ili 40 °C povećana je aktivnost lipaze potpomognuta dodatkom maslinova ulja. No, uzgojem u osnovnom mediju pri rasponu od 30 do 55 °C ta je aktivnost smanjena. Aktivnost lipolitičkih ekstrakata neznatno se smanjila dodatkom 50 % organskih otapala koja se miješaju s vodom, dok su alifatska otapala što se ne miješaju s vodom smanjila aktivnost lipaze za 20-80 %.Screening of lipolytic strains using Rhodamine-B/olive oil plate technique allowed the selection of Aspergillus niger MYA 135. Lipase production in submerged culture containing 2 % olive oil was enhanced by more than 50 % compared to basal cultural conditions. Optimal catalytic conditions for olive oil-induced lipase were pH=6.5 and 30–35 °C. These values were shifted to the acid region (4.0–6.5) and 35–37 °C when lipase extract was produced under basal conditions. Slight changes of the residual lipase activity against the pH were found. However, preincubation at either 37 or 40 °C caused an increase in the olive oil-inducible lipolytic activity. On the contrary, lipase residual activity decreases in the 30–55 °C range when it was produced in basal medium. Lipolytic extracts were almost not deactivated in presence of 50 % water-miscible organic solvents. However, water-immiscible aliphatic solvents reduced the lipase activity between 20 and 80 %

Biotransformations

Selective conversions of natural and/or synthetic substrates into useful products using whole cells or isolated enzymes have been gaining increase relevance among the methods at industrial scale. Enzymatic activity is often characterized due to its high chemo-, regio- and stereo-selectivity, which are very useful for synthesis of fine chemicals and intermediary molecular blocks. However, the success of a biotransformation at industrial scale depends upon a series of factors such as availability and low cost of the biocatalyst, efficient product recovery processes, competitive costs compared to conventional methods, environmental compatibility, and non-pathogenicity of the biological systems. This chapter highlights general aspects of biocatalysis, recent findings and new strategies about modes of using enzymes and fluids in the biotransformation field.Centro de Investigación y Desarrollo en Fermentaciones Industriale