Process Optimization And Organic Acid Analysis Of Naringinase Production Improved By Fungi Co-culture

Naringinase is a hydrolytic enzyme consisting of a-L-rhamnosidase and ?-D-glucosidase,which can hydrolyze natural glycosides to produce many important pharmaceutical chemical intermediates.However,the industrial development of naringinase is limited due to low production capacity and expensive cost.Co-culture technology,as a new fermentation strategy,can effectively increase target product yields,and it is promising for the application of biochemical,pharmaceutical and food industry.In this work,the fermentation characters were optimized to improve the activity of naringinase,and then the organic acid of naringinase production by fungi co-culture was analyzed.The flat transparent circle method was firstly used for screening naringinase production strains,and the naringinase activity was highest via Aspergillus niger FFCC uv-11 and Rhizopus FFCC 3201 co-culture.Then the effects of various fermentation parameters on naringinase liquid fermentation process via fungi co-culture were investigated.The optimal fermentation conditions were as follows:the inoculation time interval was 36 h,the inoculation volume was 10%,the inoculation ratio of Aspergillus niger FFCC uv-11 to Rhizopus FFCC 3201 was 2:1,the initial pH was 5.5 and the total fermentation time was 72 h.The naringinase activity reached 733.19 U·mL-1,which was 2.22 times higher than that not optimized conditions(330.00 U·mL-1).Meanwhile,the ?-glucosidase activity reached 77.02 U·mL-1,which was 1.43 times higher than that of 53.91 U·mL-1 under not optimized condition.Furthermore,the organic acids metabolism of fungi pure culture and fungi co-culture fermentation were determined by GC-MS combined with HPLC.It was indicated that Aspergillus niger FFCC uv-11 could produce oxalic acid,lactic acid,acetic acid and citric acid,and Rhizopus FFCC 3201 could produce oxalic acid,lactic acid and acetic acid.When Aspergillus niger FFCC uv-11 and Rhizopus FFCC 3201 were co-cultured,there were oxalic acid and acetic acid in the fermentation broth.The naringinase activity was 330.00 U·mL-1 via co-culture fermentation under not optimized condition,which was 1.22 times and 4.20 times of Aspergillus niger FFCC uv-11 and Rhizopus FFCC 3201 pure culture.The ?-glucosidase activity of co-culture was 53.91 U·mL-1,which was 1.23 times and 5.57 times of Aspergillus niger FFCC uv-11 and Rhizopus FFCC 3201 pure culture.The results showed that there might be some synergistic impacts between Aspergillus niger FFCC uv-11 and Rhizopus FFCC 3201 during co-culture fermentation,which enhanced the naringinase activity,and further affected the metabolism of organic acids.This study provided basic data for exploring naringinase co-culture fermentation process,increasing naringinase activity and making sure the regulatory mechanisms of naringinase production,which has great significance for promoting naringinase industrialization process.