ABSTRACT
Inulinase (ß-2,1-D- fructan fructanohydrolase), EC 3.2.1.7, targets the ß-2,1 linkage of inulin, a polyfructan consisting of linear ß-2,1 linked fructose, and hydrolyzes it into fructose. This use provides an alternative to produce fructose syrup through the hydrolysis of inulin. The objective of this work was to study the production, characterization and applications of inulinases from the fungal endophyte CCMB 328 isolated from the Brazilian semi-arid region. Response Surface Methodology (RSM) was employed to evaluate the effect of variables (concentration of glucose and yeast extract), on secreted inulinase activities detected in the culture medium and also in the inulin hydrolysis. The results showed that the best conditions for inulinase production by CCMB 328 are 9.89 g / L for glucose and 1.09 g / L for yeast extract. The concentration of 0.20 mol/L of NaCl and KCl increased the activity of inulinase from CCMB 328 by approximately 63% and 37%, respectively. The results also showed that the inulinase has potential for inulin hydrolysis, whose conversion yields roughly 72.48 % for an initial concentration of inulin at 1% (w/v).
Subject(s)
Fungi/enzymology , Glycoside Hydrolases/biosynthesis , Brazil , Desert Climate , Glycoside Hydrolases/chemistryABSTRACT
Microbial pectinolytic enzymes are known to play a commercially important role in a number of industrial processes. The objective of this study was to investigate the extracellular polygalacturonases of yeasts isolated from Brazilian semi-arid environments. Among the 250 colonies tested, only 33 produced extracellular polygalacturonases: Aureobasidium pullulans (18 isolates), Candida boidinii (one isolate), Trichosporonoides sp. (three isolates), Kluyveromyces marxianus (one isolate), Cryptococcus liquefaciens (one isolate), Pseudozyma sp. (four isolates), and yeast-like related to fungal endophyte (five isolates). The highest activity of polygalacturonase was observed in Pseudozyma sp. CCMB 300 (14.17+/-0.08 micromol acid galacturonic released/min/mg protein). This study shows the potential of yeasts and yeast-like organisms isolated from Brazilian semi-arid environments to produce pectinolytic enzymes.
Subject(s)
Fungal Proteins/metabolism , Polygalacturonase/metabolism , Yeasts/enzymology , Brazil , Databases, Nucleic Acid , Desert Climate , Food Technology/methods , Food-Processing Industry/methods , Fungal Proteins/genetics , Fungi/classification , Fungi/enzymology , Fungi/genetics , Fungi/isolation & purification , Genes, Fungal , Pectins/metabolism , Phylogeny , Polygalacturonase/genetics , Polymerase Chain Reaction , RNA, Ribosomal/chemistry , RNA, Ribosomal/genetics , Sequence Homology, Nucleic Acid , Symbiosis , Yeasts/genetics , Yeasts/isolation & purificationABSTRACT
The use of inulinases provides an alternative to the chemical process of inulin hydrolysis to obtain fructose syrup, and can reduce processing steps, time, and costs in the food industry. The objective of this work was to screen the thermostable inulinases produced by yeast and yeast-like strains isolated from the Brazilian semi-arid region. Thermostability was studied at different temperatures (60 degrees C, 70 degrees C, 80 degrees C and 90 degrees C) and for increasing periods of time (0-50 min). Thirty-three microorganisms were tested, and 27 showed inulinase activity with specific activities ranging from 0.98 to 73.79 micromol/mg protein/min. Three strains (CCMB 300, CCMB327 and CCMB328) showed the desired combination of high specific activity and a small reduction in residual activity when submitted to heat treatment (>or=60 degrees C). Our results indicate that the inulinases produced by these three yeast strains from the Brazilian semi-arid region have great potential to be used for inulin hydrolysis in the food industry.
