Enhancement of dihydroxyacetone production by a mutant of Gluconobacter oxydans

Production of dihydroxyacetone from an aqueous solution of glycerol in the reaction catalyzed by an immobilized cell preparation of acetic acid bacteria Gluconobacter oxydans ATCC 621

“…The active center of GlyDH is located in the periplasmic space, which enables lesser consumption of energy required for the transport of substrates into and products outside the cell [12,24,29]. Due to a strongly hydrophobic character and low stability of the purified fraction of GlyDH, it is difficult to determine the spatial structure of this enzyme [20,22,23]. The optimal activity of GlyDH obtaining from cells of acetic acid bacteria of the genus Gluconobacter is observed in the pH range of 7.0-8.0 [4,20] and in the temperature range of 23-25°C [1].…”

“…The course of this reaction may be disturbed by the inhibiting effect of a glycerol substrate or/and the product formed on the metabolic activity of acetic acid bacteria and activity of GlyDH [9,22,24]. Apart from DHA, the postreaction mixture contains other bacterial metabolites that impede purification and crystallization of DHA [6].…”

Bioconversion of Biodiesel-derived Crude Glycerol to 1,3 Dihydroxyacetone by a Potential Acetic Acid Bacteria

“…Among these membranebound dehydrogenase enzymes, PQQ-dependent glycerol dehydrogenase (PQQ-GLDH) shows versatility in substrate specificity and is responsible for the oxidation of glycerol to dihydroxyacetone (Matsushita et al 2003). However, the DHA-production capability of G. oxydans was seen to be influenced by several parameters such as substrate inhibition, product inhibition and oxygen limitation (Ma et al 2010). Recently, it was shown that a mutant G. oxydans M5 defective in the genes encoding alcohol dehydrogenase and aldehyde dehydrogenase exhibited higher DHA production than the wild type and yielded more DHA than could be obtained by the over-expression of glycerol dehydrogenase (Li et al 2010).…”

Production of 1,3-Dihydroxyacetone by Gluconobacter nephelii in Upflow Aerated Bioreactors with Agro-industrial Wastes as External Nitrogen Source

“…It was also served as the building block for the production of fine chemicals such as 1,2-propylene glycerol or lactic acid [2,4]. Due to wide range of applications, the demand for DHA was predicted to increase significantly, thereby requiring the production process to be both technically and economically feasible [5]. It has been suggested that the biological production of DHA is more efficient than the chemical pathways due to lesser expense required for process safety and easier product separation, and importantly DHA compounds produced biologically are more acceptable by pharmaceutical and cosmetic industries than those produced via chemical synthesis [6].…”

“…Aerated stirred tank bioreactors have been generally employed in the cultivation of Gluconobacter at various scales. In spite of the advantages such as low construction cost and ease of operation, aerated stirred tank bioreactors often experience mass and heat transfer limitation when attempting to scale up or culture at high cell density [5]. Airlift bioreactors were suggested as the possible alternatives to stirred tank bioreactors because they exhibited relative high gas-liquid mass transfer, good liquid mixing, low liquid shear force as a result of no mechanical moving parts and low operating cost [19][20][21][22].…”