Basic Studies on Anaerobic Degradation of Glucose in Continuous Stirred Tank Reactors

1991 ◽  
Vol 24 (5) ◽  
pp. 141-147
Author(s):  
Michimasa Nakamura ◽  
Atsushi Sakai ◽  
Jun'ichiro Matsumoto
Keyword(s):  
Anaerobic Degradation ◽  
Volatile Fatty Acid ◽  
Reaction Rate ◽  
Ph Value ◽  
Reaction Rate Constant ◽  
The Other ◽  
Total Volatile ◽  
Maximum Reaction Rate ◽  
Maximum Reaction ◽  
Total Volatile Fatty Acid

The two series of the characteristics of anaerobic degradation of low glucose concentrations were investigated. In the first series, the pH value in each reactor was not controlled. In the second series, the pH value in each reactor was controlled in the range of 6.9–7.2, by adding sodium bicarbonate into each influent. The ORP value was depressed by controlling the pH value of each reactor from acid range to approximately neutral range. In the pH uncontrolled series, the pH value in outflow decreased with increasing glucose concentration. In the pH uncontrolled series, produced total volatile fatty acid was about 70 to 550 mg/l; on the other hand, in pH controlled series, produced total volatile fatty acid was about 50 mg/l to 350 mg/l. The highest concentrations of acids formed were acetic acids, the second highest formed were propionic acids, the last formed were butyric acids. In the pH uncontrolled series, the maximum reaction rate constant Vm was 0.749 gCOD/gVS · day and the saturation constant Ks = 0.435 g/l. On the other hand, in the pH controlled series, the maximum reaction rate constant Vm was 1.441 gCOD/gVS · day and the saturation constant Ks = 0.739 g/l. Thus by controlling the pH value of the reactor, the activities of the anaerobic bacteria were much enhanced.

scholarly journals A Novel Sucrose Isomerase Producing Isomaltulose from Raoultella terrigena

2021 ◽  
Vol 11 (12) ◽  
pp. 5521
Author(s):  
Li Liu ◽  
Shuhuai Yu ◽  
Wei Zhao
Keyword(s):  
Ph Value ◽  
Wild Type ◽  
Michaelis Constant ◽  
Wild Type Enzyme ◽  
Maximum Reaction Rate ◽  
E Coli ◽  
Maximum Reaction ◽  
Conversion Rates ◽  
Raoultella Terrigena ◽  
Sucrose Isomerase

Isomaltulose is widely used in the food industry as a substitute for sucrose owing to its good processing characteristics and physicochemical properties, which is usually synthesized by sucrose isomerase (SIase) with sucrose as substrate. In this study, a gene pal-2 from Raoultella terrigena was predicted to produce SIase, which was subcloned into pET-28a (+) and transformed to the E. coli system. The purified recombinant SIase Pal-2 was characterized in detail. The enzyme is a monomeric protein with a molecular weight of approximately 70 kDa, showing an optimal temperature of 40 °C and optimal pH value of 5.5. The Michaelis constant (Km) and maximum reaction rate (Vmax) are 62.9 mmol/L and 286.4 U/mg, respectively. The conversion rate of isomaltulose reached the maximum of 81.7% after 6 h with 400 g/L sucrose as the substrate and 25 U/mg sucrose of SIase. Moreover, eight site-directed variants were designed and generated. Compared with the wild-type enzyme, the enzyme activities of two mutants N498P and Q275R were increased by 89.2% and 42.2%, respectively, and the isomaltulose conversion rates of three mutants (Y246L, H287R, and H481P) were improved to 89.1%, 90.7%, and 92.4%, respectively. The work identified a novel SIase from the Raoultella genus and its mutants showed a potential to be used for the production of isomaltulose in the industry.

scholarly journals The Effect of Multistage Ammoniation on Fiber Fraction and Digestibility of Maize Stover in vitro

2016 ◽  
Vol 5 (1) ◽  
Author(s):  
K. Dakaew ◽  
A. Abrar ◽  
A. Cherdthong
Keyword(s):  
Organic Matter ◽  
Fatty Acid ◽  
Volatile Fatty Acid ◽  
Dry Matter ◽  
Total Volatile ◽  
Maize Stover ◽  
Dry Matter Digestibility ◽  
Fiber Fraction ◽  
Total Volatile Fatty Acid

The main objective of this experiment was to assess the effect of multistage ammoniation on fiber fraction and digestibility of maize stover in vitro. Maize stover was treated by a multistage technique of different urea connect ration (8%, 4%, and 2%) and incubation for 14 days at room temperature.Digestibility of NDF, ADF, ADL, hemicellulose, and cellulose, in vitro dry matter digestibility (DMD), organic matter digestibility (OMD), NH3-N, total volatile fatty acid (VFA) and pH concentration were observed. However treatment maize stover and multistage ammoniation maize stover were composed by using T-test student as the statistic. There were not significantly different on fiber fraction and digestibility of maize stover. However, multistage ammoniation decreased ADF fraction by 56.67% to45.39%. The DM digestibility of multistage ammoniation on fiber fraction and digestibility of maize stover also increased by 35.18 to 45.91. The total VFA and N-ammonia of multistage ammoniation on fiber fraction and digestibility of maize stover also higher than control.Keywords: Ammoniation, Digestibility, in vitro, Maize stover

The effects of essential oil and condensed tannin on fermentation and methane production under in vitro conditions

2016 ◽  
Vol 56 (10) ◽  
pp. 1707 ◽  
Author(s):  
Brittany Pinski ◽  
Mevlüt Günal ◽  
Amer A. AbuGhazaleh
Keyword(s):  
Fatty Acid ◽  
Methane Production ◽  
Volatile Fatty Acid ◽  
Condensed Tannin ◽  
Total Volatile ◽  
Tannin Extract ◽  
Ch4 Production ◽  
N Concentration ◽  
Total Volatile Fatty Acid

The potential of five different essential oils (EO) and quebracho condensed tannin extract (QCT) as antimethanogenic additives in ruminant feeds were investigated. The first experiment was conducted to screen the effects rosemary oil, sage oil, cinnamon oil (CNO), eucalyptus oil and myrrh oil at 500 mg/L of culture fluid on methane (CH4) production under in vitro conditions. Rumen contents were collected from a cannulated Holstein dairy cow and used for a 24-h batch-culture experiment. Treatments were a control (CON) or CON plus EO at 500 mg/L. Results showed that CNO decreased CH4 production and, therefore, was selected for Experiment 2. The second experiment was designed to test the effects of CNO at three different dose levels on CH4 production and fermentation in 24-h batch-culture experiments. Treatments were CON or CON plus CNO supplemented at 125, 250 and 500 mg/L. Relative to CON, CNO decreased total gas production at the 250 and 500 mg/L doses. All doses of CNO decreased CH4 production. Total volatile fatty acid production was lower in cultures incubated with CNO at the 500 mg/L. Ammonia-N concentration decreased in cultures incubated with CNO at the 500 mg/L. The third experiment was designed to test the effects of QCT on CH4 production and fermentation in 24-h batch cultures. Treatments were CON or CON plus QCT at 25, 50 and 75 g/kg of diet DM. Relative to CON, total volatile fatty acid concentration increased with the 50 g/kg QCT, but was similar to the 25 and 75 g/kg QCT. The proportions of acetate decreased, while the proportions of propionate increased with the 25 g/kg QCT compared with CON. Methane production was not affected in cultures incubated with QCT. Relative to CON, all doses of QCT decreased ammonia-N concentration. In conclusion, results from the present study showed that except for CNO, EO tested in the study had no effects on rumen CH4 production. Addition of CNO to rumen cultures at 125 and 250 mg/L reduced CH4 production without negative effects on rumen fermentation. Quebracho condensed tannin-extract supplementation had no effects on CH4 production and fermentation parameters except for ammonia-N concentration.

FERMENTATION OF WHEAT OR LUPINS IN THE RUMEN OF SHEEP

1984 ◽  
Vol 64 (5) ◽  
pp. 29-30 ◽  
Author(s):  
R. W. HODGE ◽  
M. J. WATSON ◽  
C. KAT
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Key Words ◽  
Volatile Fatty Acid ◽  
Ammonia Nitrogen ◽  
Total Volatile ◽  
Volatile Fatty Acid Concentration ◽  
Branched Chain Fatty Acids ◽  
Branched Chain ◽  
Total Volatile Fatty Acid

The concentration of ammonia nitrogen and branched chain fatty acids was significantly higher (P < 0.05) in ruminal fluid of sheep given lupins than in those given wheat but there were no significant differences in pH, total volatile fatty acid concentration or molar proportions of acetate, propionate or butyrate. Key words: Sheep, wheat, lupins, rumen, fermentation

Effect of monensin on in vitro fermentation of maize starch by hindgut contents of cattle

1990 ◽  
Vol 115 (3) ◽  
pp. 389-392 ◽  
Author(s):  
M. Marounek ◽  
O. Petr ◽  
L. Machañová
Keyword(s):  
Fatty Acid ◽  
Methane Production ◽  
Volatile Fatty Acid ◽  
Maize Starch ◽  
Total Volatile ◽  
Molar Percentage ◽  
In Vitro Fermentation ◽  
Consistent Effect ◽  
Total Volatile Fatty Acid

SUMMARYContents of the caecum and the colon of four steers and four cows fed concentrate-plus-roughage diets were obtained at an abattoir, transferred to the laboratory and incubated anaerobically with maize starch in the presence (10mg/l) or absence of monensin. Samples taken at the end of incubation were assayed for fermentation acids and methane production.Monensin significantly increased the molar percentage of propionate and decreased that of butyrate. Acetate percentage was not significantly influence by the addition of monensin. There was no consistent effect of monensin on total volatile fatty acid concentrations. Monensin decreased methanogenesis in all incubations. The production of methane was small, only 1 mmol/13–50 mmol of volatile fatty acid.

Sign in / Sign up

Export Citation Format

Share Document