Strain Development, Substrate Utilization, and Downstream Purification of Vitamin C

Abstract

Vitamin C, C6H8O6, is a water-soluble vitamin that is widespread in nature. It is an essential nutrient involved in many biological processes in the living organisms: it enhances collagen biosynthesis, ensures the optimal functioning of enzymes and the immune system, has a major role in lipid and iron metabolism, and it enhances the biosynthesis of l-carnitine. Due to its antioxidant activity, vitamin C can neutralize the tissue-damaging effects of free radicals. Vitamin C is being related to the prevention of cancer and cardiovascular diseases. This review includes current information on the biosynthesis of ascorbic acid, as new methods are now challenging the traditional Reichstein process for vitamin C’s industrial-scale production. Different strains were analyzed in correlation with their ability to synthesize ascorbic acid, and several separation techniques were investigated for a more effective production of vitamin C.

Advances in Novel Animal Vitamin C Biosynthesis Pathways and the Role of Prokaryote-Based Inferences to Understand Their Origin

“…VC synthesis usually relies on an initial chemical conversion of D-Glucose to D-Sorbitol followed by two independent fermentation steps using Gluconobacter oxydans and a mixed culture of Ketogulonigenium vulgare and Bacillus megaterium , respectively, to obtain 2-Keto-L-Gulonic acid [ 235 ], a VC precursor. This two-step fermentation method is highly efficient, but the hydrogenation of D-Glucose and the maintenance of balanced co-cultures still have economical and labor costs that can, in principle, be avoided [ 235 ], using for instance, a direct one-step fermentation process [ 235 , 236 ]. This can be achieved through the genetic integration of plant VC synthesis pathway components, such as the A. thaliana GALDH , in fungi [ 236 ], as well as the integration of genes involved in D-Sorbitol/L-Sorbose metabolism from different prokaryote sources into a single bacterial chassis [ 237 , 238 , 239 ].…”

“…This two-step fermentation method is highly efficient, but the hydrogenation of D-Glucose and the maintenance of balanced co-cultures still have economical and labor costs that can, in principle, be avoided [ 235 ], using for instance, a direct one-step fermentation process [ 235 , 236 ]. This can be achieved through the genetic integration of plant VC synthesis pathway components, such as the A. thaliana GALDH , in fungi [ 236 ], as well as the integration of genes involved in D-Sorbitol/L-Sorbose metabolism from different prokaryote sources into a single bacterial chassis [ 237 , 238 , 239 ]. Substantial optimization is, however, required since the efficiency of VC synthesis is still dependent on the adequate availability of cofactors and/or compatible electron acceptors [ 235 , 236 ].…”

“…This can be achieved through the genetic integration of plant VC synthesis pathway components, such as the A. thaliana GALDH , in fungi [ 236 ], as well as the integration of genes involved in D-Sorbitol/L-Sorbose metabolism from different prokaryote sources into a single bacterial chassis [ 237 , 238 , 239 ]. Substantial optimization is, however, required since the efficiency of VC synthesis is still dependent on the adequate availability of cofactors and/or compatible electron acceptors [ 235 , 236 ]. Nevertheless, if the species used as chassis already has the majority of the required enzymatic components, such limitations could be overcome.…”

“…If true, P. aeruginosa could represent an additional bacterial chassis that could be explored for the purpose of VC synthesis. Given that a bioengineered P. aeruginosa acid phosphatase has already been used to convert VC to a more stable L-Ascorbic acid-2-phosphate derivative resistant to high-temperatures [ 242 ], the same bacterial species could be used for both VC synthesis and stabilization, a relevant concern in the recovery process of this nutrient [ 236 ].…”

Applications of Ion Exchange Resins in Vitamins Separation and Purification

“…The human body cannot synthesise vitamins naturally. Vitamins are taken from balanced foodstuffs to maintain the proper function and metabolism of our physiological system on an everyday basis [1][2][3][4][5][6]. The inadequate supply of vitamins leads to various diseases such as metabolic disorders, cardiac problems, diabetes and tumours also [1,[6][7][8][9][10][11][12].…”