Biochemistry of Fermentation

9.4.1 Fermentation of Carbohydrates

Carbohydrates serve as the chief source of energy in all heterotrophs with sup­plementation by proteins and fats. The metabolic sequence of energy generation from these major groups of nutrients suggests that carbohydrates are the source of

Table 9.9 Frequently used mesophilic and thermophilic microorganisms, and their optimum growth conditions

Species

Temperature

optimum(°Q

pH

optimum

Products

References

Mesophilic microorganisms

Acetobacterium woodii

30

6.8

Acetate

[49]

Butyribbacterium

methylotrophicum

37

5.8-6.0

Acetate, Butyrate, Lactate, Pyruvate

[168]

Clostridium aceticum

30

8.5

Acetate

[171]

Clostridium

autoethanogenum

37

5.8-6.0

Acetate,

ethanol

[3]

Clostridium ljungdahlii

37

6.0

Acetate,

ethanol

[184]

Clostridium

carboxidivorans

38

6.2

Acetate, ethanol, butyrate, butanol

[113]

Clostridium leatocellum 35 SG6

Thermophilic microorganisms

7-7.2

Acetate, lactate,

ethanol

[146]

Moorella

58

6.1

Acetate

[164]

thermoautotrophica

Clostridium

55

6.5-6.8

Acetate

[32]

thermoaceticum

Clostridium

60

7.5-6.0

Acetate

[47]

thermocellum

Carboxydocella

60

6.8

H2

[173]

sporoproducens

energy in the primitive form of life. In the following section, the degradation of carbohydrates, especially polysaccharides that are generally the source of energy liberated either by fermentation or through other metabolic processes, will be discussed.