Advanced in the Production of L-Ascorbic Acid using Biotechnological Processes

Over the past decade there has been increasing demand to develop alternatives to the Reichstein process, a largely chemical synthesis by which the majority of vitamin C (L-ascorbic acid) is produced. Many studies improve the biotransformation of Reichstein intermediate, but no natural bacterial strain is capable of catalyzing the biosynthesis of intermediates in single step fermentation. The study aimed to Isolate and identify bacterial strains have the ability to produce Ascorbic acid and detect their ability to be cultivated on plant wastes as substrate. In this study a total of Seventy-five different bacterial colonies of acetic acid bacteria were isolated from eight different samples. The most potent isolate was identified by 16S rRNA and phylogenetic tree relationship showed that the isolated strain was novel and named Gluconobacter oxydans st SW with accession number OP429626. The optimal levels of different nutritional and cultural variables were reached. The data revealed that the yield of ascorbic acid was increased from 7.17 g/l to 10.348 g/l. The effect of low doses of gamma radiation was tested. For Gluconobacter oxydans st. SW, the highest ascorbic acid yield was obtained was 20.480 g/l at activation radiation dose 1.2 kGy compared with 10.34 g/l from the parent isolate at the optimum fermentation conditions. It was observed that the radiated Gluconobacter oxydans st SW can adapt to the waste’s hydrolysate more than the un-radiated one. The highest yield of ascorbic acid (21.2 g/l) was obtained from fermentation broth containing 70% supplemented hydrolsate and 30% synthetic fermentation broth.