17.3 Biological Pretreatment

271

Table 17.2

Different yeasts used for sustainable bio ethanol production along with their

natural environments.

Sl. No. Yeast

Natural

environments

Details

References

1.

Candida spp.

Cyniclomyces spp.

Pityrosporum spp.

Animals

Yeasts can be pathogenic as

well as non-pathogenic to

animals and are generally

found to adhere to the

intestinal walls of the host.

[19, 20]

2.

Ashbya spp.

Nematospora spp.

Plants

Habitat includes the interface

between nutrients of plants

and the septic habitat.

[19, 20]

3.

Rhodotorula spp.

Debaryomyces spp.

Water

Inhabitants of fresh as well as

estuarine waters.

[20]

4.

Lipomyces spp.

Schwanniomyces spp.

Soil

Survives in aerobic soil.

[21]

5.

Debaryomyces spp.

Zygosaccharomyces spp.

Extreme

environmental

conditions

The yeast cells are carried by

air currents and dropped on

the surface of the soil.

[20]

6.

Cryptococcus spp.

Rhodotorula spp.

Sporobolomyces spp.

Atmosphere

Yeasts which are halotolerant

are inhabitants of salty areas.

Osmophilic species are found

on glaciers.

[15]

anaerobic co-processing of cow fertilizer which enhanced the cellulose degrada-

tion up to 80% [16, 17]. Saccharomyces cerevisiae is one of the basic microorganisms

utilized in ethanol creation since it is equipped for delivering higher amounts of

ethanol, higher resistance of ethanol, and capability of maturing wide scope of sug-

ars. There are quite a few problems in yeast-mediated fermentation, for example,

higher temperature, higher ethanol fixation, and the capacity to ferment pentose

sugars. Yeasts have the ability to straightforwardly turn basic sugars into ethanol.

The normal forms included in ethanol creation are pretreatment, hydrolysis, and

fermentation. Bioethanol while fermentation relies upon a few factors, for example,

temperature, sugar fixation, pH, aging time, fomentation rate, and size of the inocu-

lum. The efficiency of the bioethanol being produced can be improved by immobi-

lization of the yeast cells [18]. The natural environments of yeasts are highlighted in

Tables 17.2 and 17.3 consists of the biological pretreatment techniques for LCB and

corresponding benefits.

17.3

Biological Pretreatment

The hemicellulose and cellulose parts of LCB have tremendous ability to act as feed-

stock in bioethanol production. This is restricted due to the complex structure of LCB

where lignin act as a barrier for the hydrolysis, saccharification, and fermentation