Single‐step lipase‐catalyzed functionalization of medium‐chain‐length polyhydroxyalkanoates

Background Functionalization of aliphatic biopolymers such as bacterial polyhydroxyalkanoates ( PHA ) using biologically active hydrophilic moieties like sugars helps to improve the hydrophilicity and biodegradability of the biomaterial . Results The effects of reaction variables reaction time, temperature, enzyme concentration and substrate ratio on reaction rate and yield in the synthesis of poly(1'‐ O ‐3‐hydroxyacyl‐sucrose) using Candida antarctica lipase B ( EC 3.1.1.3) were studied. Using H 2 O 2 as micro‐initiator, enzyme‐mediated synthesis yielded reaction rate, v app of 0.076 x 10 −5 mol L −1 s −1 . The biodegradability of the functionalized polymer was observed to increase by 1.5 fold compared with the non‐functionalized material apart from showing better compostability. Increasing the reaction temperature (>50°C), enzyme concentration (>15 g L −1 ) and reactant ratio (w/w) of sucrose: PHA (>2) did not increase further the rate or yield. The sucrose‐functionalized mcl‐ PHA was characterized with respect to the non‐functionalized material . Conclusions Novozym® 435 can be used effectively to synthesize poly(1'‐ O ‐3‐hydroxyacyl sucrose) in micro‐aqueous medium bypassing the need for chemo‐synthetic steps. The synthesized biomaterials have potential applications in biomedical and industrial niches.© 2012 Society of Chemical Industry