Breeding Microorganism For Degrading Orange Pericarp And The Characteristics Of Special Navel Orange Clean Processing Pectinase Enzyme

With the improvement of people's living standard,the products of deep treatment of our citrus sinensis has been becoming more and more popular among consumers from home and abroad.Taking off segment membrane has become the key in deep processing of citrus sinensis.It include traditional acid-bases citrous peeling method and enzymic method.Compared with enzymic method,the traditional method to degrade the citrus sinensis endocarp is demand for workers,production efficiency is extremely low,and and unstable product quality,vulnerable to security question.In the process of citrus sinensis cleaner processing useing the enzymatic degradation of citrus sinensis,including pectinase is of crucial importance.Pectinase producted by microbial fermentation is the main resource.In this study,at first,microorganism Y-6-4 obtained screened from soil samples to degrade the citrus sinensis endocarp,and then it species relationship was identify.At last we optimized its media composition,and studied the enzymatic properties of its producing pectinase.The results obtained are as follows:1.The purpose of this research was to screen high-yield strains of pectinase from soil,and successfully obtained a high-yield strain named Y-6-4,and its capacity for pectinase activity was 169.53 U/mL.Combining morphological and molecular biological identification method,Y-6-4 was identificated as Geotrichum sp,and this bacterial strain has been delivered to the Chinese microbial culture collection management center for preservation,the registration number is:CGMCC No 10771.2.Optimization assays of single factor experiments and orthogonal experiments were done to estimate the secreted pectinase by the Y-6-4 strain and cultural conditions which expressed highest production of pectinase were studied.Research results show that the optimum enzyme producting medium consisted of:orange pericarp powder 1.00%,ammonium nitrate 0.60%,potassium hydrogen phosphate 0.10%,potassium dihydrogen phosphate 0.1%,ferrous sulfate 0.05%,magnesium sulfate 0.06%,zinc sulphate 0.04%.And the optimum fermentation conditions were:fermentation temperature 32?,fermentation time72 h,inoculum 2×10~8?/L,initial pH 5.0.Under these conditionthe enzymes was up to432.29 U/mL.3.Characterization of pectinase studies had shown that Pectinase optimum reaction temperature was 50?,and the temperature range of the thermal stability was between 4?to50?,and the optimum pH was 5,pH range of stability is 4 to 7.These properties demonstrated that this pectinase produced by Y-6-4 strain have good stabilization,and conducive to food processing and other industries in the promotion of applications.4.To compare effect on orange pericarp removing between homemade pectinase and commercial pectinase,the enzymes of homemade pectinase is 456.09 U/mL.and the enzymes of homemade pectinase is 503.57 U/mL.Control other variables unchanged,the citrus sinensis capsule can be completely removed within 2.5 h.Therefore,the results of this study were more advantageous to citrus sinensis enzymatic clean processing because cost reduction and quality improvement.