稀酸水解玉米芯制备丁二酸

利用正交设计得到稀H2SO4水解玉米芯制备混合糖液的优化工艺:玉米芯料液比1∶5(质量体积比),物料粒径250~380μm、H2SO4用量3%(体积分数)、水解温度126℃、反应时间2.5 h。此工艺条件下的总糖收率达90%,总糖质量浓度为60 g/L,发酵抑制物糠醛含量为0.87 g/L,5-羟甲基糠醛含量为0.68 g/L。在此基础上利用活性炭吸附和Ca(OH)2中和对玉米芯混合糖液进行脱毒及脱盐处理,SO42-脱除率达96%,色素脱除率为96%,糠醛、5-羟甲基糠醛及多酚类物质脱除率均高于50%。处理后的玉米芯多组分糖液作为产琥珀酸放线杆菌(Actinobacillus succino-genes)NJ113的发酵C源,当培养基中初始总糖质量浓度为50 g/L时,丁二酸收率为61.68%,丁二酸质量浓度为30.8 g/L;初始总糖质量浓度为70 g/L时,丁二酸收率仍可达50%以上,丁二酸质量浓度为35.2 g/L。发酵实验表明,将经过脱毒脱盐处理的玉米芯多组分糖液替代葡萄糖作为C源发酵制备丁二酸具有可行性。     

Effects of carbon dioxide on ethylene production and action in intact sunflower plants

A continuous flow system was used to study the interactions between carbon dioxide and ethylene in intact sunflower (Helianthus annuus L.) plants. An increase in the concentration of carbon dioxide above the ambient level (0.033%) in the atmosphere surrounding the plants increased the rate of ethylene production, and a decrease in carbon dioxide concentration resulted in a decrease in the rate of ethylene production. The change in the rate of ethylene production was evident within the first 15 minutes of the carbon dioxide treatment. Continuous treatment with carbon dioxide was required to maintain increased rate of ethylene production. The rate of carbon dioxide fixation increased in response to high carbon dioxide treatment up to 1.0%. Further increases in carbon dioxide concentration had no additional effect on carbon dioxide fixation. Carbon dioxide concentrations higher than 0.11% induced hyponasty of the leaves whereas treatment with 1 microliter per liter ethylene induced epinasty of the leaves.     

Influence of some aliphatic alcohols on the metabolism of rat liver slices

The influence of some aliphatic alcohols on oxygen uptake, carbon dioxide production, acid formation and lactate and pyruvate concentrations of rat liver slices was studied. At the concentrations used, none of the alcohols was found to influence oxygen uptake. Of the alcohols that are not oxidized by liver alcohol dehydrogenase, methanol increased carbon dioxide production, propan-2-ol decreased it and 2-methylpropan-2-ol was without influence. All the alcohols that are oxidized by the enzyme strongly decreased carbon dioxide production. The alcohols that are not oxidized had no marked effect on the lactate/pyruvate concentration ratio, whereas the other alcohols strongly increased the ratio. A highly significant correlation was found between the effects of the alcohol on pyruvate concentration and carbon dioxide production. It is assumed that the shift in the redox potential inhibits the function of the tricarboxylic acid cycle of the liver.     

Gas Exchange of Algae: III. Relation between the Concentration of Carbon Dioxide in the Nutrient Medium and the Oxygen Production of Chlorella pyrenoidosa

The oxygen production of a photosynthetic gas exchanger containing Chlorella pyrenoidosa (1% packed cell volume) was measured when various concentrations of carbon dioxide were present within the culture unit. The internal carbon dioxide concentrations were obtained by manipulating the entrance gas concentration and the flow rate. Carbon dioxide percentages were monitored by means of electrodes placed directly in the nutrient medium. The concentration of carbon dioxide in the nutrient medium which produced maximal photosynthesis was in the range of 1.5 to 2.5% by volume. Results were unaffected by either the level of carbon dioxide in the entrance gas or the rate of gas flow. Entrance gases containing 2% carbon dioxide flowing at 320 ml/min, 3% carbon dioxide at 135 ml/min, and 4% carbon dioxide at 55 ml/min yielded optimal carbon dioxide concentrations in the particular unit studied. By using carbon dioxide electrodes implanted directly in the gas exchanger to optimize the carbon dioxide concentration throughout the culture medium, it should be possible to design more efficient large-scale units.     

Effect of dissolved carbon dioxide on penicillin fermentations: Mycelial growth and penicillin production

The effect of dissolved carbon dioxide on the specific growth rate and the penicillin production rate of Penicillium chrysogenum was examined experimentally. The dissolved carbon dioxide was found to inhibit the specific growth rate and the penicillin production rate when the aerated submerged penicillin fermentation was exposed to influent gases of 12.6 and 20% carbon dioxide, respectively. Upon exposure to influent gases of 3 and 5% carbon dioxide, no pronounced metabolic inhibition was noted.     

Influence of atmospheric carbon dioxide enrichment on induced response and growth compensation after herbivore damage in Lotus corniculatus

Abstract 1. Plant growth and chemical defence compounds in four Lotus corniculatus genotypes exposed to factorial combinations of ambient and elevated carbon dioxide, and herbivory by caterpillars of Polyommatus icarus were measured to test the predictions of the carbon/nutrient balance hypothesis.
2. Shoot and root biomass, allocation to shoots versus roots, and carbon-based defence compounds were greater under elevated carbon dioxide. Pupal weight of P. icarus was greater and development time shorter under elevated carbon dioxide.
3. Herbivory decreased shoot growth relative to root growth and production of nitrogen-based defence (cyanide). Young leaves contained more defence compounds than old leaves, and this response depended on carbon dioxide and herbivory treatments (significant interactions).
4. Genotype-specific responses of plants to carbon dioxide and herbivory were found for the production of cyanide. Furthermore, maternal butterfly-specific responses of caterpillars to carbon dioxide were found for development time. This suggests the existence of genetic variation for important defence and life-history traits in plants and herbivores in response to rising carbon dioxide levels.     

Microbial contributions to the evolution of the 'steady state' carbon dioxide system.

Various processes for the production of carbon dioxide by microorganisms are presented. It is postulated that a 'microniche' developed in a reducing environment; a symbiotic relationship between alga-like organisms and bacterium-like organisms in the 'microniche' governed the production of carbon dioxide resulting in the establishment of the steady state carbon dioxide system in the sea.     

A comparison of carbon dioxide production and oxygen uptake in sediment cores from four south Swedish lakes

Carbon dioxide production and oxygen uptake were measured in undisturbed sediment cores taken during winter from four lakes of different trophic state. Respiration was measured at 5, 10, 15 and 20°C at high oxygen saturation (75–100%). The respiratory quotient, calculated from the mean values of carbon dioxide production and oxygen uptake at each temperature for each lake, was 0.83–0.96 with a mean value for the four lakes of 0.90. At very low oxygen saturations (<10%) carbon dioxide production was 21–42% of the production at 20°C and high oxygen saturations. The results indicate that under aerobic conditions, oxygen uptake and carbon dioxide production are closely-coupled processes in these lake sediments.     

Regulation of Senescence in Carnation (Dianthus caryophyllus): Effect of Abscisic Acid and Carbon Dioxide on Ethylene Production

Abscisic acid hastened senescence of carnation flowers and this was preceded by stimulation of accelerated ethylene production. Carbon dioxide delayed the onset of autocatalytic ethylene production in flowers regardless of treatment with abscisic acid. Flowers exhibited a low and transient climacteric of ethylene production without wilting while in 4% carbon dioxide and underwent accelerated ethylene production culminating in wilting when removed from carbon dioxide. Hypobaric ventilation, which lowers ethylene to hyponormal levels within tissues, extended flower longevity and largely negated enhancement of senescence by abscisic acid. Supplementing hypobarically ventilated flowers with ethylene hastened senescence irrespective of abscisic acid treatment. Collectively, the data indicate that abscisic acid hastens senescence of carnations largely as a result of advancing the onset of autocatalytic ethylene production.     

Carbon dioxide production from pyruvate and glucose by bovine oocytes

The production of carbon dioxide from radioactive pyruvate and radioactive glucose by bovine follicular oocytes was investigated. The rate of carbon dioxide production from pyruvate was 12.78 ± 0.66 pmole/oocyte/h, while the rate of production from glucose was 0.35 ± 0.07 pmole/ oocyte/h. The data suggest that the bovine oocyte relies to a considerable extent on pyruvate as an energy source.     

Study of the composition and elaboration of a catalytic method for purifying the gaseous waste from neomycin and monomycin production]

Composition of the waste gases in the production of neomycin and monomycin at the stages of fermentation, coagulation and filtration was studied. It was found that the main components of the waste gases in the production of neomycin and monomycin were carbon dioxide (0.15-6.0 mg/1), moisture (22-34 mg/1) and organic substances (0.5-4.2 mg/1) calculated for carbon dioxide. These substances have a specific unpleasant odour. A procedure for purification of the waste gases in the production of neomycin and monomycin by catalytic oxidation was developed.     

Biodegradation of rubber particles in soil

The biodegradation of rubber particles in rubber-soil mixtures at different rubber contents was monitored by the carbon dioxide production. The cumulative carbon dioxide production was modelled according to a two parameter exponential function. The model provides an excellent fit (R²>0.98) for the observed data. The two parameters yield a reliable estimate of the half-life for the process observed, but estimation of the true half-life of rubber in soil will need more research.     

Physiology of Oil Seeds: II. Dormancy Release in Virginia-type Peanut Seeds by Plant Growth Regulators

Germination, ethylene production, and carbon dioxide production by dormant Virginia-type peanuts were determined during treatments with plant growth regulators. Kinetin, benzylaminopurine, and 2-chloroethylphosphonic acid induced extensive germination above the water controls. Benzylaminopurine and 2-chloroethylphosphonic acid increased the germination of the more dormant basal seeds to a larger extent above the controls than the less dormant apical seeds. Coumarin induced a slight stimulation of germination while abscisic acid, 2,4-dichlorophenoxyacetic acid, and succinic acid 2,2-dimethylhydrazide did not stimulate germination above the controls. In addition to stimulating germination, the cytokinins also stimulated ethylene production by the seeds. In the case of benzylaminopurine, where the more dormant basal seeds were stimulated to germinate above the control to a larger extent than the less dormant apical seeds, correspondingly more ethylene production was induced in the basal seeds. However, the opposite was true of kinetin for both germination and ethylene production. When germination was extensively stimulated by the cytokinins, maximal ethylene and carbon dioxide evolution occurred at 24 and 72 hours, respectively. Abscisic acid inhibited ethylene production and germinaton of the seeds while carbon dioxide evolution was comparatively high. The crucial physiological event for germination of dormant peanut seeds was enhancement of ethylene production by the seeds.     

Systematic error in the calculated specific acid production rate in anaerobic fermentation of Lactococcus lactis in the presence of carbon dioxide

Summary The lactococci are commonly grown anaerobically, blanketed with a mixture of nitrogen and carbon dioxide. Specific acid production rate is often determined by alkali usage in constant pH fermentations. The combination of these methods leads to incorrect acid production figures because the added carbon dioxide reacts with some of the alkali.     

Effects of controlled gas environments in solid-substrate fermentations of rice

The gas environment is solid-substrate fermentations of rice significantly affected levels of biomass and enzyme formation by a fungal species screened for high amylase production. Constant oxygen and carbon dioxide partial pressures were maintained at various levels in fermentations by Aspergillus oryzae. Control of the gas phase was maintained by a “static” aeration system admitting oxygen on demand and stripping excess carbon dioxide during fermentation. Constant water vapor pressures were also maintained by means of saturated salt solutions. High Oxygen pressures stimulated amylase productivity significantly. On the other hand, amylase production was severely inhibited at high carbon dioxide pressures. While relatively insensitive to oxygen pressure, maximum biomass productivities were obtained at an intermediate carbon dioxide pressure. High oxygen transfer rates were obtained at elevated oxygen pressures, suggesting, in view of the stimulatory effect of oxygen on amylase production, a stringent oxygen requirement for enzyme synthesis. Solid-substrate fermentations were highly advantageous as compared with submerged cultures in similar gas environments. Not only were amylase productivities significantly higher, but the enzyme was highly concentration in the aqueous phase of the semisolid substrate particles and could be extracted in a small volume of liquid. Results of this work suggest that biomass and product formation in microbial processes may be amenable to control by the gas environment. This is believed to offer an interesting potential for optimizing selected industrial fermentation processes with respect to productivity and energy consumption.     

Gas Exchange of Algae: IV. Reliability of Chlorella pyrenoidosa

A single culture of Chlorella pyrenoidosa (700 ml) was grown continuously under uniform environmental conditions for a period of 11 months. During this time, the culture remained uncontaminated and its oxygen production, carbon dioxide consumption, and photosynthetic quotient (PQ = CO(2)/O(2)) were monitored on a 24-hr basis. The gas exchange characteristics of the alga were found to be extremely reliable; the average oxygen production was 1.21 +/- 0.03 ml per min, the carbon dioxide consumption was 1.09 +/- 0.03 ml per min, and the PQ was 0.90 +/- 0.01 when changes in both lamp intensity and instrument accuracy were taken into consideration. Such long-term dependability in the production of oxygen, consumption of carbon dioxide, and maintenance of a uniform PQ warrants the use of C. pyrenoidosa in a regenerative life support system for space travel.     

Performance of bacterial strains used for distillery waste treatment on different substrates

Six bacterial strains were isolated and acclimatized on distillery waste. The performance of these bacterial strains in respect to growth, reduction in chemical oxygen demand (COD) values, carbon dioxide production and volatile acid production were studied on five different substrates. Glucose and xylose exhibited growth patterns similar to that on spentwash. Glucose, xylose, casein hydrolysate and amino acids led to very good reduction in COD values compared with glycerol. Rate of substrate consumption was maximum in the case of glucose followed by amino acids, casein hydrolysate, xylose and glycerol. Production of volatile acids and carbon dioxide from glucose amounted to ≈ 50% of the theoretical yield based on glycolysis and the tricarboxylic acid cycle. Production of carbon dioxide followed the usual microbiological growth pattern while volatile acids did not show any such pattern. Carbon dioxide and volatile acids appear to be the major degradation products in distillery waste treatment by these bacteria.     

DYNAMICS OF NERVE CELLS : II. THE TEMPERATURE COEFFICIENTS OF CARBON DIOXIDE PRODUCTION BY THE HEART GANGLION OF LIMULUS POLYPHEMUS.

1. It is possible to determine by the colorimetric method the rate of production of carbon dioxide by the cardiac ganglion of Limulus. 2. Carbon dioxide formation in the cardiac ganglion was found to run parallel to the rate of heart beat for different temperatures. 3. The conclusion seems justified that the rate of cardiac rhythm of Limulus depends upon a chemical reaction in the nerve cells of the cardiac ganglion and that this reaction is associated with the production of carbon dioxide since the rate of beat and the rate of CO₂ production are similarly affected by changes in temperature.     

Photoproduction of Hydrogen by the Marine Heterocystous Cyanobacterium Anabaena Species TU37-1 Under a Nitrogen Atmosphere

Hydrogen production rates by Anabaena sp. strain TU37-1 obtained after an initial 1-day incubation period were approximately 70 to 80 and 3 to 9 µmol (mg chl)^–1 h^–1 under argon and nitrogen atmospheres, respectively. Hydrogen production under argon was not enhanced by addition of carbon dioxide, but was enhanced to some extent under nitrogen by increasing the initial carbon dioxide concentration. Rates of hydrogen and oxygen production during the initial 7-hour period were 15 and 220 µmol (mg chl)^–1 h^–1, respectively, in vessels with 18.5% initial carbon dioxide. Hydrogen production under nitrogen was enhanced by addition of carbon monoxide (1%). The rate obtained from the initial 1-day incubation period was about 40 µmol (mg chl)^–1 h^–1, which corresponded to about 60% of that under argon. On the basis of these observations, a possible strategy for hydrogen production by nitrogen-fixing cyanobacteria under nitrogen in the presence of carbon monoxide is indicated.     

Influence of sulphur dioxide on the fermentation of sulphite spent liquor

In fodder yeast production from sulphite spent liquor, sulphur dioxide is well-known as a yeast poison. The present paper deals with the detailed influence of sulphur dioxide. The experimental work was done in a laboratory fermenter under technical conditions. A decrease in biomass yield, and an increase in oxygen consumption, caused by increasing carbon dioxide production, were found. During the fermentation, there is no destruction of the carbonyl-bisulphite adduct to be observed. Sulphur dioxide has no influence on the crude protein content of yeast cells, and there is also no influence on the morphology of cells.