Gluconic acid production under varying fermentation conditions byAspergillus niger (original) (raw)
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Gluconic acid production under varying fermentation conditions by Aspergillus spp
The production of gluconic acid with respect to varying substrate concentrations in submerged (SmF), surface (SF) fermentations was analyzed. Under the various fermentation conditions the biomass and specific growth rate varied with different concentrations of glucose. The effects of pH, temperature, incubation time and concentrations of carbon were tested in submerged fermentation process in production of gluconic acid by Aspergillus spp. The highest level of gluconic acid was obtained under SmF conditions. In all cases the maximum degree of gluconic acid conversion was observed at on initial substrate concentration of 10gm/100ml. The rate of glucose uptake increased on increasing the initial glucose concentration and glucose utilization was observed to be highest in the SmF process and was comparable with the SSF and SF processes. The maximum rate of cell growth was obtained in all processes at an initial glucose concentration of 10gm. But in comparison to glucose, sucrose is more effective than glucose. The gluconic acid production and change in pH were analyzed at varying time intervals and it was observed that the SmF and SF processes were completed within 5 days of incubation whereas the highest yield was observed after 3 rd day of incubation and continued thereafter in the SmF process. The increase in production of gluconic acid corresponds to the increase in cell growth instead of Glucose Oxidase (GOD) activity.
Production of gluconic acid from glucose by Aspergillus niger: growth and non-growth conditions
Process Biochemistry, 2004
Batch fermentation of glucose to gluconic acid was conducted using Aspergillus niger under growth and non-growth conditions using pure oxygen and air as a source of oxygen for the fermentation in 2 and 5 l stirred tank reactors (batch reactor). Production of gluconic acid under growth conditions was conducted in a 5 l batch reactor. Production and growth rates were higher during the period of supplying pure oxygen than that during supplying air, and the substrate consumption rate was almost constant. For the production of gluconic acid under non-growth conditions, conducted in the 2 l batch reactor, the effect of the pure oxygen flow rate and the biomass concentration on the gluconic acid production was investigated and an empirical equation suggested to show the dependence of the production rate r p on the biomass concentration C x and oxygen flow rate Q, at constant operating conditions (30 • C, 300 rpm and pH 5.5). Biomass concentration had a positive effect on the production rate r p , and the effect of Q on r p was positive at high biomass concentrations.
Amon g the seven isolated mi crobial strai ns from dumping sites of the sugarcane industry was te, a potent funga l strain Aspergilil/s lIiger ORS-4 was selected, th at gave 48 giL of glu co ni c acid wi th 74 per ce nt yield w hen glucose was used as the ca rbon source. Starch hydrol ysa te, molasses and th e banana must were evalu ated as th e cheaper ca rbohydrate sou rces 1 '01' glu co ni c acid production by A lIiger ORS-4 in surface cu lture fermen tati on process. The banana mu st was found to be a bett er source with signi licant glucon ic acid producti on (3 9.6 gi L, 40 per cent yield) aner 12 d incubati on. The untrea ted sugarca ne mo lasses gave margi nal production of gluco ni c acid (2.4 gi L), however, th e produ cti on increased signifi ca ntl y (34. 6 giL, yield 38.5 per cent) after th e molasses were subj ec ted to th e hexacynoferrate (HCF) trea tment. Starch hydro lysate on the other hand , resulted into co mparative prod ucti on (30.2 giL, yield 35.9 per cent) but lower th an th at ob tained with HCF treated mol asses , whereas the acid production was low (10 giL) with unh ydro lyzed starch. Gluconi c acid production from these substrates was comparab le to th at obtained wi th glu cose.
Kinetic Study Of Gluconic Acid Batch Fermentation By Aspergillus Niger
2009
Gluconic acid is one of interesting chemical products in industries such as detergents, leather, photographic, textile, and especially in food and pharmaceutical industries. Fermentation is an advantageous process to produce gluconic acid. Mathematical modeling is important in the design and operation of fermentation process. In fact, kinetic data must be available for modeling. The kinetic parameters of gluconic acid production by Aspergillus niger in batch culture was studied in this research at initial substrate concentration of 150, 200 and 250 g/l. The kinetic models used were logistic equation for growth, Luedeking-Piret equation for gluconic acid formation, and Luedeking-Piret-like equation for glucose consumption. The Kinetic parameters in the model were obtained by minimizing non linear least squares curve fitting.
Journal of Microbial & Biochemical Technology, 2012
The gluconic acid batch fermentation was conducted using mutant Aspergillus niger NCIM 530 strain under submerged condition in 50 L semiautomatic stirred-tank fermenter. Certain cost-effective source as golden syrup was effectively utilized instead of glucose for successful industrial fermentation process. The significant level of gluconic acid (85.2 gL-1) production was observed with maximum 86.97% glucose conversion over 44 hours. This process provides great advantages over traditional submerged fermentation strategies and substrates, as showed by effective production of gluconic acid by utilizing novel substrate as a golden syrup. To reduce analysis time with better accuracy, an effort has been made to use a method for evaluation of parameters like conversion of substrate and production of gluconic acid during the fermentation by using High Performance Thin Layer Chromatography (HPTLC).
Applied Microbiology and Biotechnology, 1991
Gluconic acid production from corn starch hydrolysates by immobilised mycelia o f Aspergillus niger was studied in a laboratory-scale stirred fermentor at different concentrations of glucose (So) and dissolved oxygen (DO) in the culture broth. Its evolution was simulated quite well by applying the same unstructured model set up in previous experiments using stirred and airlift fermentors. In particular, increasing So in the range 70-160 g/l, although uninfluential upon the yield coefficient, resulted in an exponential decrease in the gluconic acid formation rate constant. Nevertheless, the greater the oxyen transfer rate used in the fermentor, the smaller the inhibitor effect of the higher concentrations of glucose on gluconate productivity became. This was achieved by enriching the inlet air with pure oxygen so as to maintain the DO level above 75% saturation throughout the fermentation.
Gluconic acid: Properties, applications and microbial production
Food Technology and Biotechnology
Gluconic acid is a mild organic acid derived from glucose by a simple oxidation reaction. The reaction is facilitated by the enzyme glucose oxidase (fungi) and glucose dehydrogenase (bacteria such as Gluconobacter). Microbial production of gluconic acid is the preferred method and it dates back to several decades. The most studied and widely used fermentation process involves the fungus Aspergillus niger. Gluconic acid and its derivatives, the principal being sodium gluconate, have wide applications in food and pharmaceutical industry. This article gives a review of microbial gluconic acid production, its properties and applications.
Journal of Chemical Technology & Biotechnology, 2008
BACKGROUND: Gluconic acid (GA) production by immobilized cells of mutant Aspergillus niger ORS-4.410 on polyurethane sponge (PUS) and calcium-alginate (Ca-alginate) was evaluated in repeated batches of solid state surface fermentation (SSF) and submerged fermentation (SmF) conditions, respectively, utilizing rectified grape must as carbon source. RESULTS: The passive immobilization of cells in fermentation medium solid support of having 0.4 cm 3 cube size, 4% spore suspension, 0.6 g inoculum of PUS immobilized cells at 32 • C and 2.0 L min −1 resulted in the maximum GA production (88.16 g L −1) with a 92.8% yield, while the Ca-alginate matrix with a 0.5 cm diameter bead size, 2-3% spore suspension, 15 g inoculum at 34 • C and 150 rpm agitation speed revealed 67.19 g L −1 GA with a 85.2% yield. Repeated use of PUS showed higher levels of GA (110.94 g L −1) in the third-fourth fermentation cycles with 95-98% yield and 22.50 g L −1 d −1 productivity under SSF that was 2.5-fold higher than the productivity obtained from a typical fermentation cycle, and 54% greater than the productivity obtained with repetitive use of Ca-alginate immobilized cells of A. niger under SmF. CONCLUSION: Using immobilized cells of A. niger in PUS, the rectified form of grape must can be utilized for GA production as an alternative source of carbohydrate by replacing the conventional fermentation conditions.