Sugar fermentation of microorganisms.

1, monosaccharine fermentation test
(i), experimental principle
monosaccharine fermentation is to add glucose, lactose or maltose and so on to protein water
culture
base, so that the final concentration of 0.75 to 1%. And add a certain amount of phenolic red indicator and small inverter, made of monosaccharide fermentation tube, inoculated bacteria cultured by 37 degrees C 18 to 24 hours, if you can break down the sugar-producing acid then phenolic red indicator from red yellow, if you can break down the acid has CO2 and H2 gas formation, small inverter is aggregated with air bubbles;
(ii), experimental materials
1. Bacteria: E. coli, typhoid 18 to 24 hours
agar
oblique culture.
2.
: glucose
tube, lactose fermentation tube, etc.
(iii) Experimental methods
1. Typhoid and E. coli were inoculated in glucose and lactose fermentation tubes according to the liquid inoculation method.
2. Incubate at 37 degrees C for 18 to 24 hours.
3. Observations: Because some bacteria can break down a certain sugar acid, so the medium PH dropped below 7.0, in the phenolic red indicator, the medium color from red to yellow. The acid-producing person indicates that if a gas is produced at the same time, bubbles appear in the medium's small inverter tube, which is acid-producing and gas-producing, and is expressed as "⊕", without decomposition, the indicator does not change color, with "-" as the indication.
(iv), experimental results
thyroid Bacillus E. coli
glucose and ⊕
lactose - ⊕
II, V-P (Voges-Proskauer) test
(i), experimental principles
some Bacteria such as gas-producing bacteria, decomposing glucose to produce acetone acid, acetone acid dehydration, the production of acetyl methyl methanol, in an alkaline environment is oxidized to diacetyl, and then combined with the culture base necide to produce red
compounds
, V-P test positive.
(ii), experimental materials
1. Bacteria: E. coli, gas-producing bacteria 18 to 24 hours agar slope culture.
2. Culture: Glucose proteinwater culture.
3.
reagents
: V-P reagents (40% potassium hydroxide solution (containing 0.3% crea acid) and 6% α-naphenol alcohol solution).
(iii) the experimental method
. 1. Inoculated against E. coli, the production of Bacillus gas in two glucosewater.
2. After 48 hours of culture at 37 degrees C, remove 1 ml of KOH1ml and α-naphenol solution, shake well, and set aside
tet tube
rack for 5 to 15 minutes.
(iv) and the experimental results
the culture liquid became red as positive and the invaricose color was negative.
3, methyl red test
(i), experimental principle
some bacteria such as E. coli and other decomposing glucose to produce acetone acid, and then decomposed into formic acid, acetic acid, lactic acid, etc., so that the culture base PH value dropped below 4.5, add methyl red instructions The agent is red, which is positive, if the amount of acid produced is small or the resulting acid is further converted into alcohol, aldehyde, gas and water, then the
acid and alkali
degrees of the culture is still above PH 6.2, the methyl red indicator is yellow, negative reaction.
(ii), experimental materials
. 1. Bacteria: E. coli, gas-producing bacteria 18 to 24 hours agar slope culture.
2. Culture: Glucosewater culture.
3. Reagents: Methyl Red Reagents.
(iii) the experimental method
. 1. E. coli and Bacillus gas produced were inoculated in two glucosewater mediums.
2. Set 37 degrees C culture 2 to 3 days to remove, respectively, add methyl red reagents 2 to 3 drops, mix well, observe the results.
(IV), the experimental results
E. coli: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4. Sodium
acid is the only carbon source and ammonium dihydrohydrogen
phosphate is the only nitrogen source . General bacteria can use ammonium dihydrohydrogen phosphate as a nitrogen source, but not necessarilydecompose radon to obtain carbon source. For this reason, according to the possibility of using radonacid to identify bacteria, such as gassacs can be used as a carbon source, bacteria grow and reproduce, the formation of moss, decomposition of datesacid to produce alkaline carbonates, so that the culture pH rose to 7.0 Above, from green to dark blue, test positive for the use of radonate, while E. coli can not break down theacid, can not get carbon source, can not grow, sterile moss formation, the color of the culture base does not change, for the use of radonate test negative.
(ii), experimental materials
. 1. Bacteria: E. coli, gas-producing bacteria 18 to 24 hours agar slope culture.
2. Culture base: acid slope.
(iii) the experimental method
. 1. E. coli, which produces Bacillus gas, was inoculated in two and acid ramp cultures.
2. The results were observed after 24
24
at a temperature of 37 degrees C.
(iv), the experimental results
production of Bacillus gas: ( bacteria moss growth, culture base color change)
E. coli: - (sterile moss growth, culture base unchanged color
.