PURIFICATION, CHARACTERIZATION AND APPLICATION OF THERMOSTABLE EXO-POLYGALACTURONASE FROM STREPTOMYCES ERUMPENS MTCC 7317

Abstract

ABSTRACT Exo-polygalacturonase (exo-PG) has a wide range of applications in food processing, i.e., juice extraction, clarification of wine, bakery and distillery industries. Culture parameters for optimum production of extracellular exo-PG by thermostable Streptomyces erumpens Microbial Type Culture Collections 7317 were found to be incubation period (36 h), pH (7.0) and temperature (50C). Enzyme production was higher in beef extract (1%) as nitrogen source as compared with others (casein, peptone, yeast extract, ammonium nitrate, etc.). The purified enzyme (by ammonium sulfate precipitation) had a molecular mass of 63.0 kDa in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Crude PG from S. erumpens was compared with marketed pectinase (Pectinex, Novozyme, Bagsvaerd, Denmark) in extraction of juice from vegetables (beet roots, carrot and sweet potato) and fruits (guava and pineapple). A 15–20% increase in juice yield was observed from vegetables and fruits with application of S. erumpens PG over Pectinex. PRACTICAL APPLICATIONS The results showed that a moderately thermostable exo-polygalacturonase (exo-PG) was produced by the actinomycetes strain Streptomyces erumpens MTCC 7317 in submerged fermentation. This enzyme can be used in extraction, clarification and depectinization of vegetables and fruit juices whose pHs are around 7.0. Furthermore, the efficiency of the enzyme has been compared with that of standard pectinase (Pectinex, Novozyme, Bagsvaerd, Denmark) for extraction of juice from vegetables (i.e., beet root [Beta vulgaris L.], carrot [Daucus carota L.] and sweet potato [Ipomoea batatus L.]) and fruits (i.e., guava [Psidium guava L.] and pineapple [Ananas comosus L.]). There was 15–20% increase in juice yield from these vegetables and fruits with the application of crude S. erumpens exo-PG over Pectinex.