Many species belonging to the genus Clostridium are categorized as strict anaerobes because neither they nor key enzymes inside them are able to function normally during aerobic culti-vations, and stringent anaerobic conditions are required for their growth (1). Despite the gen-eral understanding about the sensitivity of clostridial species to O2, some strains possess me-tabolic mechanisms for withstanding, to some degree, the presence of dissolved oxygen (DO), and this phenomenon has been reviewed(2,3). Clostridium acetobutylicum strain ATCC 824, a widely investigated model for studies on the fermentative production of butanol, sus-tained growth after a shift from anaerobic to microoxic conditions (0-0.2 % DO)at the mid-exponential phase of growth, however, it ceased to grow on flushing the broth with a gas mixture of 5 % O2 / 95 % N2 (4).The O2-tolerance of C. acetobutylicum strain ATCC 824 in microoxic conditions has been attributed to the production of O2-induced polypeptides, which are presumed to play a protective role against toxic activated oxygen species such as superoxide anion and hydrogen peroxide (4).Studies on the oxygen stress-responses in the obligate anaerobes C. acetobutylicum and C.aminovalericum revealed the upregulation of gene clusters coding for O2-scavenging enzymes, including NADH : rubredoxin oxidoreductase (EC 1.18.1.1), glutathione peroxidase (EC 1.11.1.9), thiol peroxidase (EC 1.11.1.1), alkylhydroperoxide reductase (EC 1.11.1.15), and superoxide dismutase (5).Based on the findings of Kawasaki et al. (4,5), Hillman et al. (6) reported that C. acetobutylicum strain ATCC 824 perRmutants, survived aerobic incubation on agar plates for up to 50 days (6). The per mutants also survived oxidative stress in aerated liquid cultures for up to 3 hours before a decrease in cell viability was observed (6). However, at this stage (after 3 hours) if no further O2 was added to the broth culture, the perR mutants were able to reestablish anaerobic conditions by rapidly consuming DO in the broth (6). These reports (4,5,6) however, did not investigate the effects of oxidative stress on the production of solvents. Despite the presence of metabolic mechanisms in some clostridia for surviving short-term oxidative stress, these appear to be insufficient for establishing long-term survival under aerobic conditions.
Literature on the effects of oxidative stress on butanol-producing bacteria, all of which are strict anaerobes, remains limited. A fuller understanding of the effects of such stressants on metabolite production will provide insights into stress-specific responses in bu-tanol-producing bacteria and may reveal strategies for improving the yield of solvents.
Investigation to Find the Relative Energy Release of Five Alcohols: Ethanol, Methanol, Propanol, Butanol and Propanol Aim: In this experiment I will investigate to see which alcohol releases the most energy during combustion; Methanol, Ethanol, Propanol, Butanol or Pentanol. Hypothesis: I think that the alcohols with the longest carbon chains will release the most energy. This is because when a bond is broken energy is released. This means that the alcohols with longer chains and therefore more
The three remaining trials were the experimental groups containing Benzoic Acid and Camphor separately with tert-butanol. 6.305 of tert-butanol was placed in a large test tube, the same amount was used for each trial. The solution was then brought to 50 C using a hot-plate. The temperature was monitored and recorded by a Lab Quest 2 Connected Sciences System. The test tube was
Analysis: 2. Of the alcohols tested 1-Butanol was found to contain the strongest intermolecular forces (IMF) of attraction, with Methanol containing the weakest. It was discovered through experimentation that Methanol induced the highest ?T of all alcohols tested, and that conversely 1-Butanol induced the lowest ?T. The atomic structure of all four alcohols is very similar, as starting with 1-Butanol a CH2 group is lost as you move from 1-Butanol to 1-Propanol to Ethanol and then again to Methanol
to determine which products are formed from elimination reactions that occur in the dehydration of an alcohol under acidic and basic conditions. The process utilized is the acid-catalyzed dehydration of a secondary and primary alcohol, 1-butanol and 2-butanol, and the base-induced dehydrobromination of a secondary and primary bromide, 1-bromobutane and 2-bromobutane. The different products formed form each of these reactions will be analyzed using gas chromatography, which helps understand stereochemistry
point from out side references so I can compare it to the other readings in the other trails. The freezing point for the tert-Butanol is below 25o C ("Tert-Butanol."). As we can see in the table above the freezing point was decreasing as we go down. In this experiment, I was able to change some chemical properties that led to a change of the physical properties of the tert-Butanol. As the additives had been added to the solvent, the chemical construction of the molecules (intermolecular) of the solvent
continue to be synthesised from the butanol and ethanoic acid until the point where the absence of the limiting reagent prevents further condensation from taking place. Butanol can be considered as the limiting reagent, preventing the total yield of butyl ethanoate which is obtained. Once all of the butanol has been consumed through the reaction with ethanoic acid, the reaction will continue in the reverse direction in an attempt to rejuvenate the supply of butanol. The reverse of condensation is referred
Purpose/Introduction: In this experiment, four elimination reactions were compared and contrasted under acidic (H2SO4) and basic (KOC(CO3)3) conditions. The acid-catalyzed dehydration was done on 2-butanol and 1-butanol; a 2ᵒ and 1ᵒ alcohol, respectively. The base-induced dehydrobromination was performed on 2-bromobutane and 1-bromobutane; isomeric halides. The stereochemistry and regiochemistry of the four reactions were analyzed by gas chromatography (GC) to determine product distribution (assuming
1a), the alcohol that will heat up the water in the least weight loss will be Butanol. This should be followed by Propanol, then Ethanol and finally, the alcohol that will grace us with most weight loss will be Methanol. This is also backed up by the secondary data I obtained from the data book. That is as follows: Methanol -715 kJ per mole Ethanol -1371 kJ per mole Propanol -2010 kJ per mole Butanol -2673 kJ per mole Overall I will take three recordings for ethanol, and measure
When Alcohols Burn I am investigating how different types of alcohol's effect the amount of energy given off. The types of alcohol used will be; Alcohol Formulae · Methanol CH3 OH · Ethanol C2 H5 OH · Propanol C3 H7 OH · Butanol C4 H9 OH I am going to investigate the amount of energy given out by the creating of bonds by subtracting the amount of energy needed to break the bonds to the amount given out from the creating of bonds. Methanol; C H3 OH + O2 ® CO2 + 2H2O
structure of the alcohol. Outline: I will use Methanol, Ethanol, Propanol and Butanol in the experiment. I will use these four because they should give me clear results, and they range from short chained to long-chained hydrocarbons, so patterns should be easy to spot in the conclusion. Variables: My independent variables are - The type of alcohol (I will use ethanol, methanol, propanol and butanol) My dependant variables are - the specific heating capacity of water - Mass
In this study, a three step purification of alkaline phosphatase from non-pasteurized milk was reported. It included cream extraction, n-butanol treatment and acetone precipitation. Different parameters like buffer concentration, temperature, pH, substrate concentration, acetone and n-butanol treatment were optimized to maximize the enzyme activity. The enzyme was fruitfully purified upto homogeneity from the milk, with percentage recovery and fold purification of 56.17 and 17.67 respectively. The
and total mass of solution was calculated as 12.7 g after adding whiskey to butanol. Next the individual standard solutions were prepared the concentration of each individual standard is calibrated to determine retention time. For each 8µL of all three solutions were transferred to 10 ml bottle then 40% ABV solution of 10 ml of ethanol in water was added to 10 ml bottle. Finally mixed standard solution was prepared so butanol of 1000 ppm was transferred to 50 ml bottle and its mass was recorded and
stored in it therefore the more bonds the more energy is stored and more energy is released if these bonds break through combustion. Theoretical Values: Methanol CH OH 17000 J/g Ethanol C H OH 22000 J/g Propanol C H OH 25000 J/g Butanol C H OH 27000 J/g Hexane C H 35000 J/g Variables: The variables used in this experiment are: Volume of water, mass of fuel, temperature of water, height of tube, height of flame, type of fuel, time it takes, width of flame, colour of
level diagram of an endothermic reaction. It shows that more energy is used breaking bonds than is used to make them. Number and Range I plan to use five alcohols in this experiment. The alcohols I will use are; methanol, ethanol, propanol, butanol and octanol. It is important that I use five alcohols so that there are enough results to spot any patterns. The experiments are to be done three times so that an average can be taken this will make the results more reliable because any anomalous
How much energy is produced when burning five alcohols · Methanol · Ethanol, · Propanol, · Butanol · Pentanol. The aim is to find out how much energy is produced when burning these alcohols. The reaction that is involved in burning alcohols is exothermic because heat is given out. Form this reason the reactant energy is higher than that of the product. The energy is given out when forming the bonds between the new water and carbon dioxide molecules. The amount of energy produced by such exothermic