Sugar Feed Research Articles

Optimization of the Performance of Packed Bed Fermentor with Immobilized Zymomonas Mobilis for the Production of Fuel Alcohol

Heterogeneous compartmental model is used to optimize the performance of a packed bed fer-mentor with immobilized zymomonas mobilis for the production of fuel alcohol. The results indicate that the outlet ethanol concentrations have maximum values that decreased with increasing feed sugar concentration at single bead diameter. The outlet ethanol concentrations have maximum values that increased with decreasing the dilution rate. As the dilution rate increased the ethanol production increased. As the substrate inhibition constant (K1) increased both the maximum outlet ethanol concentration and the optimum feed sugar concentration increased up to K1 value of 500 g/L above that each have constant value.

Female Aedes aegypti (Diptera: Culicidae) in Thailand rarely feed on sugar.

Female Aedes aegypti (L.) of two different body sizes and provided with different diets (20% sucrose, water only, or 20% sucrose + human blood) were marked and released together in a rural Thai village. Recaptured marked and unmarked (wild) adults were tested for fructose by the cold-anthrone reaction. Both released and wild females showed a low frequency of sugar feeding in nature; both small-bodied and large-bodied individuals failed to sugar feed significantly. Marked females released with sugar in their crop utilized this energy source over the following 2-3 d but failed to replenish it. In contrast, about one-third of wild, resting males showed evidence of recent sugar feeding. This indicated that the absence of plant sugar in females was not caused by a shortage of nectar sources in this rural domestic environment. Presumably, the nonutilization of plant sugar as an energy source increases the frequency of blood feeding and, therefore, the vectorial capacity of Ae. aegypti.

Advanced control of glutathione fermentation process

A study was performed to understand the fermentation process for production of glutathione fermentation (GSH) with an improved strain of baker's yeast. Simultaneous utilization of sugar and ethanol has been found to be a key factor in the industrial process to produce GSH using Saccharomyces cerevisiae KY6186. Based on this observation, the optimal sugar feed profile for the fed-batch operation has been determined. A feedforward/feedback control system was developed to regulate the sugar feed rate so as to maximize GSH production yields. Using the feedforward/feedback control system and the on-line data of oxygen and ethanol concentration in exhaust gas, the successful scaleup to the production level was accomplished. An average of 40% improvement of glutathione production compared to a conventionally programmed control of exponential fed-batch operation was found in the new process.

Process engineering studies on continuous ethanol production by immobilized S. cerevisiae

Saccharomyces cerevisiae cells were immobilized on three supports—calcium alginate beads, raw and hexamethylene diamine treated bagasse—for their comparative assesment in terms of cell retention on to the carrier and metabolic and physiological activities of the immobilized cells. The chosen carrier-activated bagasse adsorbed 0.41 g of cells per g of carrier (on a dry weight basis). The Gibbs free energy and activation energy for immobilization for the first and second stages was computed to be 3272.45, 14624.27 and 6336.34 J g mol −1, respectively. The immobilized cells were used in a packed bed reactor for the continuous bioconversion of sucrose to ethanol and the packing density of the carrier and the height to diameter ratio of the packed bed bioreactor were optimized to be 50 g l t-1 and 2.5, respectively. The maximum productivity obtained was 31.8 g l t-1 h t-1 at a feed sugar concentration of 200 g l t-1 and space velocity of 0.53 h -1. The system was operationally stable in terms of productivity for 76 days. The system then could be reactivated by intermittent air sparging for further operation.

NADH fluorscence in a carbon‐limited fermentation

The continuous flow acetone-butanol fermentation conducted at lowered inlet feed sugar concentrations and at a constant dilution rate D =0.075 h(-1) demonstrated a significant decreases in the availability of the cell population "reduction energy" (F/X), resulting in an exclusive accumulation of intermediate acids under those conditions. The cultures resumed its solvent production activity when the inlet sugar concentration in the feed stream was increased from 20 to 40 g/L at the same low growth/dilution rates. A linear correlation between the culture reduction content (F/X) and the specific butanol rate (q(B)) was observed under the present conditions, indicating the necessity of the NADH availability for the increased solvent production.

Gonotrophic Cycle Duration, Population Age Structure, and Onset of Sugar Feeding and Insemination of Aedes triseriatus (Diptera: Culicidae)

During two successive summers, laboratory-reared Aedes triseriatus (Say) were marked and released into two woodlots in central Ohio. Several cohorts of two groups of mosquitoes were marked and released: blood-engorged, 10-12-d-old females and unfed, 2-d-old females. The parity of marked mosquitoes captured during daily biting collections were used to estimate the duration of the gonotrophic cycle. The parity rate of unmarked mosquitoes, in conjunction with the cycle estimate, yielded data on age structure and daily survival. Information on the onset of insemination and sugar feeding also was obtained. The mean and median duration of the first gonotrophic cycle, based on females released after blood feeding and later finding the collector, was 12 d. Unfed females required a median of about 8 d to feed on sugar, mate, and locate the collector, but required 22-32 d to sugar feed, mate, find a natural host, become parous, and then find the collector. The median duration of the natural gonotrophic cycle was estimated to take 14 d during warm (22 degrees C) weather. The parity rate of the natural population remained between 29 and 51% during the last 3 mo of each summer. The high proportion parous indicated that daily survival rate of unmarked females was above 0.9. Marked females moved between woodlots for distances as far as 400 m and were more likely to emigrate from the small woodlot than the large one.

Bioconversion of sugars to ethanol in an immobilized cell packed bed bioreactor - dynamic response to perturbations in process parameters

Saccharomyces cerevisiae cells ionically adsorbed onto hexamethylene-diamine-treated bagasse (maximum cell loading 0.410 g cells per gram of carrier, dry basis) were used in a packed bed bioreactor at 30 ± 1 °C with sucrose medium (pH 5.0). The dynamic behaviour resulting from perturbations in feed sugar concentration and feed flow rate was studied during the continuous bioconversion of sugar to ethanol. The time-dependent partial differential equations were solved numerically by the Crank-Nicolson method and the experimental data fit well with those computed from the model. The RNA and total protein levels and alcohol dehydrogenase enzyme activity during the transient phase were monitored in a continuous stirred tank bioreactor (free cells) and their levels provide a reasonable explanation of the experimentally observed behaviour.

Facultative blood‐feeding in the crabhole mosquito, Deinocerites cancer

1. Most of the female crabhole mosquitoes Deinocerites cancer Theobald entering bait traps had undeveloped ovaries. 2. Nearly half of the D. cancer females that were captured in bait traps, but denied blood, were gravid following a 1 week holding period; they developed relatively small egg clutches autogenously (mean = 7.4 eggs per gravid female). 3. Although both parous and nulliparous D. cancer females were captured exiting from crabholes, only parous females were attracted to and collected in bait traps. 4. Much larger egg clutches (mean = 41.8 eggs per female) were produced anautogenously by mosquitoes that blood-fed on chickens. 5. All D. cancer females from field collected pupae developed eggs autogenously when allowed to mate and sugar feed in the laboratory. These mosquitoes produced an initial egg clutch with a mean size equivalent to that found in blood-fed, parous mosquitoes from bait traps. 6. In the field, mating and sugar feeding rather than blood-feeding seem to stimulate production of the initial egg clutch. 7. D. cancer blood-feeding appears to be delayed until after the first egg clutch has been laid; some parous crabhole mosquitoes are facultative blood feeders and can produce an egg clutch either with or without a blood meal.

Application of expert fuzzy controller in the penicillin fermentation processes

The expert fuzzy control system of the penicillin fermentation processes is developed in the paper which can recognize different fermentation phases and adopt related control strategies. Feed rates are controlled according to PH value and penicillin productive rate. The fuzzy control models of sugar feed rate are established. Finally, two illustrative examples are given to show that the control strategies developed is feasible and reliable for real plants.

Separation of sugars by continuous annular chromatography

Continuous chromatographic separations of aqueous fructose-glucose-sucrose solutions have been investigated in a laboratory-scale continuous annular chromatograph (CAC) using calcium-exchanged Dowex 50W-X8 resin. Comparative studies have also been conducted using a conventional fixed-bed column packed with the same resin. Complete resolution of fructose-glucose mixtures could be obtained both in a 60-cm-long CAC and in a conventional column of the same length with a sugar feed concentration of up to 200 g/L. Partial resolution of sucrose in three component mixtures was also obtained, and the three sugars were completely separated from added higher-molecular-weight saccharides. Results have been analyzed in terms of approximate linear chromatographic theories and orthogonal collocation of exact mass transfer model equations for fixed and rotating beds. A systematic, comparative evaluation of factors affecting process performance and design procedures is presented.

A numerical evaluation of a hollow fiber extractive fermentor process for the production of ethanol

The economics of a process for the production of ethanol employing a hollow fiber extractive fermentor have been investigated. A computer simulation of the process incorporating a mathematical model of the fermentor was used to calculate the mass and energy balances. The results of the process simulation were read into a computer spreadsheet programmed with the economic calculations from which a final ethanol product cost was obtained. The process was found to be as competitive as conventional fermentation processes even at the currently high cost--$4/sq ft--of hollow fibers. It was determined that the 1986 price of 46.2 cents/L of ethanol produced by the process would be reduced by 1.8 cents/L for every $1/sq foot drop in the price of hollow fibers. A comparison of this process with conventional fermentation processes indicates that its potential savings lie in its ability to use a concentrated sugar feed, and the fermentor's increased productivity and ability to produce a concentrated ethanol stream which is removed by the extracting solvent.

Modelling and adaptive control of fed‐batch penicillin fermentation

AbstractThis paper describes a study to investigate the application of state estimation and parameter adaptive control in fed‐batch fermentation for penicillin production. A model of the penicillin fermentation process is outlined and shown to be capable of matching industrial data. The penicillin mould biomass is controlled to a reference trajectory by applying self‐tuning control to an estimate of biomass, obtained from measurements of carbon dioxide production rate and fermenter volume and by using the fermentation model with an extended Kalman filter. The manipulated variable, sugar feed to the fermenter, is calculated by an adaptive algorithm. Simulation results compare the performance of self‐tuning control with that obtained using digital Proportional plus Integral control.

Online estimation and adaptive control of penicillin fermentation

The paper describes an investigation into the application of state estimation and adaptive control to fed-batch fermentation for penicillin production. The work forms part of an industrial collaborative project, the aim of which is the optimising control of large fed-batch fermenters. Estimates of biomass are made using an extended Kalman filter from on-line measurements of carbon dioxide production rate and fermentation volume. The estimated biomass is controlled to a reference trajectory by an adaptive generalised predictive controller manipulating the sugar feed rate. A comparison of performance is made with control by conventional proportional plus integral (PI) techniques. The results presented are obtained from simulation studies while validation studies are carried out on both a 30 1 pilot plant fermenter and the industrial plant.

Fuzzy Control Application to Glutamic Acid Fermentation

Consumption rate of ammonia in glutamic acid fermentation was found to be correlated with consumption rate of sugar. This gives a good control strategy for sugar feed rate to keep sugar concentration in a suitable range in fed-batch culture of glutamic acid fermentation.Slight changes of culture conditions, however, make some troubles in this control scheme. Fuzzy theory application could be found to be effective in such cases.

Immobilization of Kluyveromyces marxianus cells containing inulinase activity in open pore gelatin matrix: 2. Application for high fructose syrup production

Batch and continuous production of high fructose syrup from Jerusalem artichoke tubers has been studied using yeast cells immobilized in open pore gelatin matrix. In a batch reactor, the hydrolysis was 93% ( d-fructose/ d-glucose = 90/10 ) and 42 mg d-fructose per ml was produced from the artichoke tuber extract by immobilized cells in 3 h. The same immobilized cells were recycled and used repeatedly for 10 batch cycles starting with fresh juice at the beginning of each cycle. It was found that immobilized cells were extremely stable and the percent hydrolysis was almost constant for all 10 batch cycles. In a continuous reactor using an immobilized cell concentration of 65.7 g (dry wt) l −1 of total working bioreactor volume, the percent hydrolysis was found to remain constant at ∼100% at dilution rates <1.26 h −1, but beyond that it decreased. Volumetric productivity attained its maximum value at D = 2.08 h −1 and was found to be 100 g l −1 h −1. This was achieved at a feed sugar conversion of 80%. At 90% conversion and D = 1.66 h −1, the productivity was found to be 90 g l −1 h −1. Continuous operation of the immobilized cell bioreactor at a constant dilution rate of 1.65 h −1 for 240 h resulted in only 2% loss of original activity.

Ethanol from whey: Continuous fermentation with cell recycle

The production of ethanol from cheese whey lactose has been demonstrated using a single-stage continuous culture fermentation with 100% cell recycle. In a two-step process, an aerobic fed batch operation was used initially to allow biomass buildup in the absence of inhibitory ethanol concentrations. In the anaerobic ethanol-producing second step, a strain of Kluyveromyces fragilis selected on the basis of batch fermentation data had a maximum productivity of 7.1 g ethanol/L/h at a dilution rate of 0.15 h(-1), while achieving the goal of zero residual sugar concentration. The fermentation productivity diminished when the feed sugar concentation exceeded 120 g/L despite the inclusion of a lipid mixture previous shown to enhance batch fermentation productivities.

Utilization of cellulosic materials through enzyamtic hydrolysis. I. Fermentation of hydrolysate to ethanol and single-cell protein.

Ethanol fermentation studies were conducted with Saccharomyces cerevisiae ATCC "4126, to determine the optimal conditions of oxygen tension and feed sugar concentration. In long-term continuous culture maximum ethanol production was found to occur at 0.07 mmHg oxygen tension and 10% glucose feed concentration. Preliminary process design and cost studies are developed for industrial scale fermentations to produce ethanol and torula yeast from sugars obtained by enzymatic hydrolysis of newsprint.

Microbial aspects of fermentation process development

AbstractAspects of fermentation dynamics are discussed, especially from the point of view of process development. Initial examples are from laboratory work in continuous culture. After this the economic and dynamic aspects of protein production by continuous culture are reviewed. In the last part the optimisation of the pencillin fermentation is considered, based on the use of a model which predicts yields, with a fermentation limited by the rate of oxygen transfer to the culture, when penicillin production falls at low growth‐rates. A process involving a sugar feed is considered, the main factors being the concentration of nitrogen in the medium, which governs initial cell production, and sugar feed rate which maintains further growth. The model predicts high yields over a wide variety of conditions. This indicates the difficulty of a pilot‐plant optimisation programme, when the maximum yield point is not critical. Other factors in the fermentation are also discussed.

The Digestion of Sucrose by the Piglet

SUMMARY Pigs of 2–18 days of age have been fed on diets containing 20 per cent of either glucose, sucrose or invert sugar. On the sucrose and invert sugar diets a marked fructosaemia occurred within 40 minutes of the feed, rising to maximum levels of 30–100 mg./100 ml. after 2–3 hours and falling to below 5 mg./100 ml. 8–10 hours after the feed. At the age of 5 or 6 days the fructosaemia produced by the invert sugar feed was approximately twice that produced by the sucrose diet but, in 17-day-old pigs, sucrose and invert sugar produced similar degrees of fructosaemia. Some fructosuria occurred on both the sucrose and invert sugar diets. Weight gains on the 3 diets were not significantly different.

THE EFFECT OF ORAL HYPOGLYCEMICS ON BLOOD SUGAR LEVEL OF TURKEYS

Blood sugar determinations were made on 8- to 13-week-old turkey males before and after being treated with the oral hypoglycemics Tolbutamide (Orinase) and Phenformin. Normal blood sugar level, for birds sampled [Formula: see text] hours after commencement of feeding following a 10-hour fast, ranged from 208 to 277 milligrams per cent. They averaged 227 milligrams per cent with a S.D. of 14.71.Orinase at 0.25 grams per bird (approximately 60 milligrams/kilogram body weight), administered orally in tablet form, caused a reduction of 27 to 44 per cent in blood sugar level within 2 hours. This had not fully returned to normal 7 hours after treatment. Limited data indicated that Phenformin was ineffective as an oral hypoglycemic when administered, dissolved in water, at levels of 0.25 gram and 0.5 gram per bird.Orinase as a feed additive at 2,000 p.p.m. of diet had no effect on blood sugar level, feed consumption or weight gains.