Institute of Microbiology, commonly used biochemical reactions in microbiological testing

Different microorganisms grow and reproduce in a certain medium , The characteristics of the colonies formed are very different , Microbial biochemical reaction refers to the determination of microbial metabolites by chemical reaction , Biochemical reactions are often used to identify microorganisms that are not easily distinguished in morphology and other aspects . Therefore, microbial biochemical reaction is one of the important bases in microbial classification and identification . Biochemical reactions commonly used in microbiological testing include ：

(1)、 Glycolysis test

The ability of different microorganisms to decompose and utilize sugars varies greatly , Be able to use or be unable to use , Exploiter , Or gas production or no gas production . Indicators and fermentation tubes can be used to test .

(2)、 Starch hydrolysis test

Some bacteria can produce enzymes that break down starch , Hydrolyze starch to maltose or glucose . After starch hydrolysis , It will no longer turn blue when encountering iodine .

(3)、v-p test

Some bacteria can decompose glucose to produce pyruvate in Glucose Peptone aqueous medium , Pyruvate condensation , Decarboxylation to acetylmethyl methanol , The latter is under strong alkali environment , Oxidized by oxygen in the air to diacetyl , Diacetyl reacts with guanidine in peptone to form a red compound , call v-p(+) reaction .

(4)、 Methyl red (methyl red) test

Every genus of Enterobacteriaceae can ferment glucose , Pyruvate is produced in the process of decomposing glucose , Further decomposition , Because of the different ways of glucose metabolism , It can produce lactic acid , Succinic acid 、 Acetic acid, formic acid and other acid products , The medium ph Value drops to ph4.5 following , Turn methyl red indicator red .