Optimization of gluconic acid synthesis by removing limitations and inhibitions

Abstract

The optimization task was performed using the gluconic acid synthesis by the Acefobucter methonolicrrs MB 58 strain. The microorganisms were grown continuously on methanol as the growth substrate. After finishing the growth process by the deficiency of N and P, the gluconic acid synthesis was started by adding glucose. The synthesis process was performed continuously. The oxygen transfer rate depended on the gluconic acid concentration. During the growth process, the oxygen transfer rate reached a value of about 13 g 0,. kg-I . h -I using a 30-1 glass fermenter equipped with a 6 blade stirrer and fully baffled. This rate declined to a value of between 2 and 5 g 0, . kg-I . h -' in the presence of gluconic acid concentrations above 150 g gluconic acid . kg-' medium. The yield (g gluconic acid . g-glucose) depended on the gluconic acid concentration and amounted to y = 0.7 in relation to 150 g gluconic acid . kg-I medium and y = 0.8 in relation to 200 g . kg-medium, respectively.The fermenters were coupled with ultrafiltration moduls (Fa. ROMICON and Fa. SARTORIUS). The biomass concentrations amounted from 5 to 40 g dry mass kg-' medium. The ultrafiltration modules retained the biomass within the fermentation system. A glucose solution (30 t o 50 weight percent glucose) was continuously dosed into the fermenter. The retention time was chosen between 2 and 30 h. The gluconic acid synthesis rate reached values of up to 32 g gluconic acid. kg-I . h-'. Within a range of up to 250 g gluconic acid . kg-' medium, the acid concentration had no influence on the enzyme activity.

Nano-Gold Catalysis in Fine Chemical Synthesis

“…Gluconic acid and its salts are important chemical intermediates and extensively used as a food and beverage additive and water-soluble cleaning agents. Currently, production of gluconic acid and its salts is based on biochemical transformation, , which is complicated by the large amounts of waste produced. Synthesis of gluconic acid with catalytic oxidation methods is a good choice in industry but is severely restricted due to the low catalyst efficiency and stability, Scheme .…”

Gluconic Acid Production in Bioreactor with Immobilized Glucose Oxidase Plus Catalase on Polymer Membrane Adjacent to Anion‐Exchange Membrane

“…The processes for the production of gluconic acid can be classified into three categories: the homogeneous catalytic, heterogeneous catalytic and biochemical processes. The use of biochemical processes for production of gluconic acid has significant advantages 2–8. The currently preferred method for preparation of gluconic acid, oxidation of glucose in air catalyzed by immobilized GOD, has attracted much attention in the past two decades and lead to thorough research and development of various means of immobilization and their use in various bioreactors 9–14.…”

“…A number of authors have studied the gluconic acid inhibition on enzyme reaction and efficient removal of gluconic acid from the enzyme reaction medium 1,2,4. To reduce gluconic acid inhibition, H. Ferraz et al proposed neutralization of gluconic acid with NaOH, but a loss of enzyme activity was observed 15.…”