2. Fungal pretreatment

The biological pretreatment can be categorized into bacterial consortium, fungal treatments and enzymatic treatments [4, 8]. The commonly utilized microorganisms in this pretreatment of lignocellulosic biomass are filamentous fungi, which can be easily found in the environment such as ground, living plants and lignocellulose wastes [9]. Wood-decay fungi are classified into three main groups, which are white-, brown- and soft-rot fungi [10]. Among them, the most effective are basidiomycetes white-rot fungi because they have the capability to degrade lignin from the holocellulose (cellulose and hemicellulose) surface [2, 7, 9, 11] and cause white-rot on wood or trees, whereas brown- and soft-rot fungi degrade only minimal lignin [6]. Lignin is a polyaromatic polymer that gives rigidity to lignocellulose [7, 11]. Previous studies on three types of rot fungi were presented in Table 2.

#### 2.1 White-rot fungi

White-rot fungi differ significantly in the relative rates at which they attack lignin and carbohydrates in woody or lignocellulosic tissues [6, 17]. They can be differentiated by their delignification mode, named as selective and non-selective delignification as can be seen in Figure 1. In selective delignification, mostly lignin and hemicellulose are degraded, while consuming a small amount of cellulose. However, for non-selective delignifiers, all three lignin, hemicellulose and cellulose are degraded almost equally [6, 18]. Even the number of non-selective white-rot fungi is greater than selective white-rot fungi [11], more than 1500 fungi species are selective delignifiers [6]. These fungi are favored for fungal pretreatment in recent researches to ensure a lignin-free and cellulose-rich biomass for next hydrolysis step [3, 7, 17] and enhance the biomass digestibility [3, 18]. Some of the white-rot fungi species were shown in Figure 2.

## 2.2 Enzymatic systems of white-rot fungi

The white-rot fungi play a major role in degrading woods in forest ecosystems [9]. These fungi have the ability to degrade lignocellulosic biomass during their growth in nature owing to the production of two enzymatic systems, which are hydrolytic system and oxidative ligninolytic system [7, 17]. In hydrolytic system, cellulases and hemicellulases are utilized to degrade holocellulose [17]. Nonselective white-rot fungi cause substantial cellulose loss because of their high cellulolytic and hemicellulolytic activity. Conversely, selective white-rot fungi excrete hemicellulolytic enzymes and employ hemicellulose-derived sugars as the main carbon sources [7].

Physical

40

Objective

 Reduce particle size, increase surface area and reduce

cellulose crystallinity

Type

• • • • •

Advantage

• Low

• Low dangerous chemical requirement

• High

• Short process time

• High uniformity and selectivity

Drawback

• High energy requirement

• •

Corrosiveness

equipment

• •

• Long process time

> Table 1.

Pretreatment

 strategies of

lignocellulosic

 biomass.

Production

 of inhibitors

Chemical recovery

 of

Toxicity

•

Chemical recovery and

• Long process time

• Large space requirement

• Need continuous

 monitoring

microorganism

 growth

 of

recycling

• High operation cost

•

Formation of inhibitors

• High cost

effectiveness

environmental

 impact

• Less dangerous process

• Less

•

Higher energy

efficiency

• Short process time

corrosiveness

•

• No chemical requirement

• Low energy

consumption

Environmental

 friendly

condition

• Lack of by-products

degradation

Radiation

Freezing

Chipping

Grinding

Milling

Chemical Hydrolyze lignin,

and cellulose

• Acid

• Steam explosion

• • •

Enzymatic

Biomass for Bioenergy - Recent Trends and Future Challenges

Fungal

Microbial consortium

> •

Ammonia fiber

expansion

• CO2

• Liquid hot water

• Wet oxidation

explosion

•

• Ionic liquid

•

Organosolv

Alkaline

hemicellulose

Breakdown

holocellulose

 linkages

 lignin-

Physicochemical

Biological

Degrade lignin from

holocellulose

 components


#### Table 2.

Previous studies on fungal pretreatment using three different types of rot fungi.

The main enzymes in ligninolytic system to degrade lignin and open the phenyl

[5, 7, 17, 20]. Nevertheless, not all of these enzymes are secreted by fungal cultures [7]. Lignin peroxidase (EC 1.11.1.14), also known as ligninase, is a heme-protein involves in oxidizing and/or cleaving of non-phenolic aromatic lignin moieties and similar molecules. Manganese peroxidase (EC 1.11.1.13) is a heme-containing glycoprotein, aids delignification by catalyzing reaction that oxidizes phenolic compounds in the presence of Mn2+. Laccases (EC 1.10.3.2) are copper-containing oxidase enzymes that act on phenols and similar molecules by executing oneelectron oxidations [5–7]. Versatile peroxidase (VP) is regarded as the third peroxidase, a LiP-MnP hybrid as it is capable of degrading both phenolic and non-

White-rot fungi of species (a) Abortiporus biennis, (b) Ceriporiopsis subvermispora, (c) Coriolopsis trogii,

The sugarcane bagasse was subjected to fungal pretreatment by P. ostreatus and C. subvermispora for a period of 60 days [18]. At the end of pretreatment, P. ostreatus homogeneously degraded all the lignocellulose components of lignin, xylan and glucan up to 11.1, 15.7 and 8.4%, respectively. C. subvermispora yielded

rings are lignin peroxidase (LiP), manganese peroxidase (MnP) and laccase

(d) Ganoderma applanatum, (e) Irpex lacteus and (f) Trametes versicolor [19].

phenolic lignin compounds and Mn2+ [6, 7].

Fungal Pretreatment of Lignocellulosic Materials DOI: http://dx.doi.org/10.5772/intechopen.84239

Figure 2.

43

2.3 Pretreatment of lignocelluloses with white-rot fungi

#### Figure 1.

Mechanism of fungal pretreatment using white-rot fungi on lignocellulosic materials.

Fungal Pretreatment of Lignocellulosic Materials DOI: http://dx.doi.org/10.5772/intechopen.84239

#### Figure 2.

Substrate Fungi species Effect References

degradation of 50.3, 18.1 and 21.4% • Sugar recovery increased by approximately

• Sugar recovery decreased by 10.9%

• On lignin over hemicellulose and cellulose

hemicellulose and cellulose at 5% each

• Mass loss ranged between 6 and 8% during the first month of biodegradation

• Weight reduction of 12.4% after 2 months of

hemicellulose and cellulose of 9%

approximately to 5 and 3%

[12]

[13]

[14]

[15]

[16]

(white-rot) • Lignin, hemicellulose and cellulose

27.6%

(brown-rot) • 37.6 and 13.3% of hemicellulose and cellulose removal

• Higher degradability

than lignin and cellulose

rot) • Preferential degradability on hemicellulose

(white-rot) • Loss of lignin at 16%, while both

(white-rot) • Lignin degradation of 16%, whereas

individually

rot) • Hemicellulose and glucans content reduced

(soft-rot) • 2.5% of weight loss after decayed for 2 months

incubation

Previous studies on fungal pretreatment using three different types of rot fungi.

Mechanism of fungal pretreatment using white-rot fungi on lignocellulosic materials.

Wheat straw

Moso bamboo

Radiata pine

Table 2.

Figure 1.

42

Ganoderma lobatum

Biomass for Bioenergy - Recent Trends and Future Challenges

Gloeophyllum trabeum

Phanerochaete chrysosporium (white-

G. trabeum (brown-

Trametes versicolor

Stereum hirsutum

G. trabeum (brown-

Xylaria acuta (soft-rot)

Scots pine Daldinia concentrica

rot)

White-rot fungi of species (a) Abortiporus biennis, (b) Ceriporiopsis subvermispora, (c) Coriolopsis trogii, (d) Ganoderma applanatum, (e) Irpex lacteus and (f) Trametes versicolor [19].

The main enzymes in ligninolytic system to degrade lignin and open the phenyl rings are lignin peroxidase (LiP), manganese peroxidase (MnP) and laccase [5, 7, 17, 20]. Nevertheless, not all of these enzymes are secreted by fungal cultures [7]. Lignin peroxidase (EC 1.11.1.14), also known as ligninase, is a heme-protein involves in oxidizing and/or cleaving of non-phenolic aromatic lignin moieties and similar molecules. Manganese peroxidase (EC 1.11.1.13) is a heme-containing glycoprotein, aids delignification by catalyzing reaction that oxidizes phenolic compounds in the presence of Mn2+. Laccases (EC 1.10.3.2) are copper-containing oxidase enzymes that act on phenols and similar molecules by executing oneelectron oxidations [5–7]. Versatile peroxidase (VP) is regarded as the third peroxidase, a LiP-MnP hybrid as it is capable of degrading both phenolic and nonphenolic lignin compounds and Mn2+ [6, 7].

### 2.3 Pretreatment of lignocelluloses with white-rot fungi

The sugarcane bagasse was subjected to fungal pretreatment by P. ostreatus and C. subvermispora for a period of 60 days [18]. At the end of pretreatment, P. ostreatus homogeneously degraded all the lignocellulose components of lignin, xylan and glucan up to 11.1, 15.7 and 8.4%, respectively. C. subvermispora yielded obvious lignin and xylan removal while consuming minimal glucan at 48, 47 and 13.6%, correspondingly. With sugarcane bagasse as the biomass, P. ostreatus behaves non-selectively due to the fact that the digestibility is not enhanced even when it degrades both lignin and polysaccharides. In contrast, C. subvermispora shows selective behavior as it removes lignin and xylan while sustaining glucan, which further improved the digestibility.

content was almost the same, 7.3 and 6.7%, correspondingly. Both fungi are selective delignification, since the degradation of cellulose starts only after 60 days of

were pretreated for 21 days using the white-rot fungus Irpex lacteus [24]. The highest lignin removal was detected using corn stover (45.8%) as the feedstock, followed by wheat straw (42.3%), barley straw (31.0%) and corncob (17.1%). For glucan digestibility, the increment was significant for corn stover (up to 59.2%), wheat straw (up to 54.8%) and barley straw (up to 53.9%), except for corncob (reduced to 30.3%). The increase in xylan digestibility was observed in corn stover (up to 82.1%), wheat straw (up to 78.0%) and barley straw (up to 58.2%),

but not for corncob (decreased to 22.4). Generally, all residues showed a reduction in lignin content. In the case of glucan and xylan digestibility, only corncob yielded lower digestibility after treatment. However, to be specific, I. lacteus behaves differently when subjected to different types of raw materials. The lignin, hemicellulose and cellulose biodegradation of oil palm empty fruit

bunches was investigated by exploiting two white-rot fungi, P. ostreatus and P. chrysosporium [25]. The lignin degradation was higher with P. ostreatus (51.9%) than with P. chrysosporium (42.1%) after treating for 21 days. In contrast, lower hemicellulose and cellulose degradation rates were noted for P. ostreatus (13.8 and 7.6%) compared to P. chrysosporium (27.7 and 28.2%). Since only a small amount of cellulose was degraded, fungal pretreatment using P. ostreatus is acceptable for palm residues. The fungus P. ostreatus can be considered as a selective delignifier because the cellulose degradation happens only after the 21 days of treatment, whereas P. chrysosporium is a non-selective delignifier as it concurrently breaks down lignin

Ishola et al. [26] found that fungal pretreatment improved the digestibility of oil palm empty fruit bunches by 4.5 times. The digestibility of untreated bunches was only 3.4%. This value was raised to 15.4% after the bunches were pretreated by Pleurotus floridanus fungus. After the pretreatment, the percentage of total lignin removal was very low, which is reduced by 0.03%. The hemicellulose content was increased by 4.4%, whereas the cellulose was decreased by 5.0% due to fungal

Enhancement of hemicellulose accessibility was reported when fresh poplar wood (Populus tomentosa) was treated for 56 days with a common white-rot fungus on angiosperm wood,Trametes velutina [27]. Comparison between untreated and fungi-pretreated material revealed that lignin degradation can positively impact hemicellulose conversion. This was proven with the reduction in lignin content by 7.2% has resulted to an increase in both hemicellulose and cellulose content by 1.0 and 6.4%, consecutively. These findings suggested that lignin degradation rendered xylan more susceptible to xylanase and that in turn rendered cellulose more sus-

For woody materials and agricultural residues feedstock, the ligninolytic systems and the appropriate fungal strains for the delignification may be different as they have different structure and chemical composition. Hence, it is important to discover the most significant white-rot fungal strain by assessing the strains for the highest degradation ability with the lowest holocellulose utilization as fungal selection subjects to the lignocellulosic biomass chosen for processing [11, 18]. Moreover, one fungus yields a very large difference of the decayed lignin-hemicellulosecellulose ratio from another fungus, even when using different strains of the same species [6]. Some of recent researches on fungal pretreatment were tabulated in

Four agricultural residues (wheat straw, corn stover, barley straw, and corncob)

incubation.

Fungal Pretreatment of Lignocellulosic Materials DOI: http://dx.doi.org/10.5772/intechopen.84239

and structural carbohydrates.

ceptible to cellulase.

Table 3.

45

attack on the linkage between lignin and carbohydrate.

The biodegradability of wheat straw and oak wood chips treated with the whiterot fungi C. subvermispora and L. edodes was observed for 56 days [21]. Using wheat straw as the feedstock, C. subvermispora reached higher lignin, hemicellulose and cellulose degradation of 83.3, 80.5 and 20.2% than L. edodes with the values of 71.7, 69.3 and 12.2%, respectively. Different observation was found when choosing oak wood chips as the biomass. C. subvermispora achieved lower lignin, hemicellulose and cellulose removal of 53.5, 50.6 and 17.4% than L. edodes with the values of 60.6, 56.3 and 37.3%, correspondingly. Both fungi selectively degraded lignin in wheat straw and wood chips but with different strategy. C. subvermispora colonizes the biomass predominantly during the first 7 days and breaks lignin and hemicelluloses without growing, whereas L. edodes constantly grows and removes lignin during the growth. The relative lower lignin removal of wood chips compared to wheat straw indicates that the fungi had more difficulty to penetrate the wood chips due to its dense structure.

In a research done on pretreatment of willow sawdust via the white-rot fungi A. biennis and Leiotrametes menziesii, it was revealed that A. biennis was more preferable for fungal pretreatment even though it has lower delignification than L. menziesii, because it consumed a very low amount of cellulose [22]. After 30 days of treatment, the lignin, hemicellulose and cellulose loss attained by A. biennis were 17.1, 19.3 and 7.4%, respectively. On the other hand, higher lignin, hemicellulose and cellulose removal was achieved by L. menziesii, with the corresponding values of 30.5, 42.4 and 26.6%.

Xu et al. [23] reported that within 12 days of pretreatment, the highest lignin loss achieved by medicinal mushroom, Inonotus obliquus, using wheat straw as substrate is at 72%, with cellulose loss of 55%. However, lower delignification was observed for corn stover and rice straw of 47 and 39% with cellulose reduction of 55 and 45%. The hemicellulose content of wheat straw, corn stover and rice straw were decreased to 46, 39 and 44%, respectively. From these results, I. obliquus shows its potential as a delignifier of agricultural biomass as it can produce high-activity-level ligninolytic and hydrolytic enzymes.

T. versicolor and S. hirsutum showed selective delignification characteristics during the pretreatment of radiata pine wood chips [14]. Both fungi have the largest selectivity value on 21 days of treatment, with T. versicolor exhibited better selectivity than S. hirsutum. Both of T. versicolor and S. hirsutum delignified the chips by 16%. The hemicellulose and cellulose was reduced at 5% each for T. versicolor whereas 9% each for S. hirsutum. As the treatment period was increased, the selectivity values of both fungi decreases because cellulose was degraded together with lignin.

The delignification properties of two white-rot fungi, rainbow fungus (T. versicolor) and edible oyster fungus (P. ostreatus), on solid oriental beech wood (Fagus orientalis Lipsky) was studied for 120 days [10]. For both fungi, there is no substantial difference observed on lignin and cellulose degradation, with lignin degradation was more effective in the first 30 days of exposure. After 120 days of incubation,T. versicolor and P. ostreatus decayed lignin by 57.4 and 56.5%, and cellulose by 16.7 and 13.9%, respectively. Meanwhile, the decrease in total carbohydrate content was significantly higher for the first 30 days using T. versicolor as compared to P. ostreatus. At the end of the exposure period, the total carbohydrate

obvious lignin and xylan removal while consuming minimal glucan at 48, 47 and 13.6%, correspondingly. With sugarcane bagasse as the biomass, P. ostreatus behaves non-selectively due to the fact that the digestibility is not enhanced even when it degrades both lignin and polysaccharides. In contrast, C. subvermispora shows selective behavior as it removes lignin and xylan while sustaining glucan,

The biodegradability of wheat straw and oak wood chips treated with the whiterot fungi C. subvermispora and L. edodes was observed for 56 days [21]. Using wheat straw as the feedstock, C. subvermispora reached higher lignin, hemicellulose and cellulose degradation of 83.3, 80.5 and 20.2% than L. edodes with the values of 71.7, 69.3 and 12.2%, respectively. Different observation was found when choosing oak wood chips as the biomass. C. subvermispora achieved lower lignin, hemicellulose and cellulose removal of 53.5, 50.6 and 17.4% than L. edodes with the values of 60.6, 56.3 and 37.3%, correspondingly. Both fungi selectively degraded lignin in wheat straw and wood chips but with different strategy. C. subvermispora colonizes the biomass predominantly during the first 7 days and breaks lignin and hemicelluloses without growing, whereas L. edodes constantly grows and removes lignin during the growth. The relative lower lignin removal of wood chips compared to wheat straw indicates that the fungi had more difficulty to penetrate the wood chips due to its

In a research done on pretreatment of willow sawdust via the white-rot fungi A. biennis and Leiotrametes menziesii, it was revealed that A. biennis was more preferable for fungal pretreatment even though it has lower delignification than L. menziesii, because it consumed a very low amount of cellulose [22]. After 30 days of treatment, the lignin, hemicellulose and cellulose loss attained by A. biennis were 17.1, 19.3 and 7.4%, respectively. On the other hand, higher lignin, hemicellulose and cellulose removal was achieved by L. menziesii, with the corresponding values

Xu et al. [23] reported that within 12 days of pretreatment, the highest lignin loss achieved by medicinal mushroom, Inonotus obliquus, using wheat straw as substrate is at 72%, with cellulose loss of 55%. However, lower delignification was observed for corn stover and rice straw of 47 and 39% with cellulose reduction of 55 and 45%.

The hemicellulose content of wheat straw, corn stover and rice straw were

fungi decreases because cellulose was degraded together with lignin.

The delignification properties of two white-rot fungi, rainbow fungus (T. versicolor) and edible oyster fungus (P. ostreatus), on solid oriental beech wood (Fagus orientalis Lipsky) was studied for 120 days [10]. For both fungi, there is no substantial difference observed on lignin and cellulose degradation, with lignin degradation was more effective in the first 30 days of exposure. After 120 days of incubation,T. versicolor and P. ostreatus decayed lignin by 57.4 and 56.5%, and cellulose by 16.7 and 13.9%, respectively. Meanwhile, the decrease in total carbohydrate content was significantly higher for the first 30 days using T. versicolor as compared to P. ostreatus. At the end of the exposure period, the total carbohydrate

decreased to 46, 39 and 44%, respectively. From these results, I. obliquus shows its potential as a delignifier of agricultural biomass as it can produce high-activity-level

T. versicolor and S. hirsutum showed selective delignification characteristics during the pretreatment of radiata pine wood chips [14]. Both fungi have the largest selectivity value on 21 days of treatment, with T. versicolor exhibited better selectivity than S. hirsutum. Both of T. versicolor and S. hirsutum delignified the chips by 16%. The hemicellulose and cellulose was reduced at 5% each for T. versicolor whereas 9% each for S. hirsutum. As the treatment period was increased, the selectivity values of both

which further improved the digestibility.

Biomass for Bioenergy - Recent Trends and Future Challenges

dense structure.

of 30.5, 42.4 and 26.6%.

44

ligninolytic and hydrolytic enzymes.

content was almost the same, 7.3 and 6.7%, correspondingly. Both fungi are selective delignification, since the degradation of cellulose starts only after 60 days of incubation.

Four agricultural residues (wheat straw, corn stover, barley straw, and corncob) were pretreated for 21 days using the white-rot fungus Irpex lacteus [24]. The highest lignin removal was detected using corn stover (45.8%) as the feedstock, followed by wheat straw (42.3%), barley straw (31.0%) and corncob (17.1%). For glucan digestibility, the increment was significant for corn stover (up to 59.2%), wheat straw (up to 54.8%) and barley straw (up to 53.9%), except for corncob (reduced to 30.3%). The increase in xylan digestibility was observed in corn stover (up to 82.1%), wheat straw (up to 78.0%) and barley straw (up to 58.2%), but not for corncob (decreased to 22.4). Generally, all residues showed a reduction in lignin content. In the case of glucan and xylan digestibility, only corncob yielded lower digestibility after treatment. However, to be specific, I. lacteus behaves differently when subjected to different types of raw materials.

The lignin, hemicellulose and cellulose biodegradation of oil palm empty fruit bunches was investigated by exploiting two white-rot fungi, P. ostreatus and P. chrysosporium [25]. The lignin degradation was higher with P. ostreatus (51.9%) than with P. chrysosporium (42.1%) after treating for 21 days. In contrast, lower hemicellulose and cellulose degradation rates were noted for P. ostreatus (13.8 and 7.6%) compared to P. chrysosporium (27.7 and 28.2%). Since only a small amount of cellulose was degraded, fungal pretreatment using P. ostreatus is acceptable for palm residues. The fungus P. ostreatus can be considered as a selective delignifier because the cellulose degradation happens only after the 21 days of treatment, whereas P. chrysosporium is a non-selective delignifier as it concurrently breaks down lignin and structural carbohydrates.

Ishola et al. [26] found that fungal pretreatment improved the digestibility of oil palm empty fruit bunches by 4.5 times. The digestibility of untreated bunches was only 3.4%. This value was raised to 15.4% after the bunches were pretreated by Pleurotus floridanus fungus. After the pretreatment, the percentage of total lignin removal was very low, which is reduced by 0.03%. The hemicellulose content was increased by 4.4%, whereas the cellulose was decreased by 5.0% due to fungal attack on the linkage between lignin and carbohydrate.

Enhancement of hemicellulose accessibility was reported when fresh poplar wood (Populus tomentosa) was treated for 56 days with a common white-rot fungus on angiosperm wood,Trametes velutina [27]. Comparison between untreated and fungi-pretreated material revealed that lignin degradation can positively impact hemicellulose conversion. This was proven with the reduction in lignin content by 7.2% has resulted to an increase in both hemicellulose and cellulose content by 1.0 and 6.4%, consecutively. These findings suggested that lignin degradation rendered xylan more susceptible to xylanase and that in turn rendered cellulose more susceptible to cellulase.

For woody materials and agricultural residues feedstock, the ligninolytic systems and the appropriate fungal strains for the delignification may be different as they have different structure and chemical composition. Hence, it is important to discover the most significant white-rot fungal strain by assessing the strains for the highest degradation ability with the lowest holocellulose utilization as fungal selection subjects to the lignocellulosic biomass chosen for processing [11, 18]. Moreover, one fungus yields a very large difference of the decayed lignin-hemicellulosecellulose ratio from another fungus, even when using different strains of the same species [6]. Some of recent researches on fungal pretreatment were tabulated in Table 3.


Substrate

47

Rice straw Radiata pine

T. versicolor

S. hirsutum

> Beech wood

T. versicolor

P. ostreatus

> Corn stover

Wheat straw

Barley straw

Corncob

I. lacteus

50 v/w%

 7.3–8.5%

 30

 N.S 21

 N.S • •

• Lignin loss was 42.3%

•

• Lignin removal up to 31.0%

• • •

Glucan and xylan digestibility

 reduced to 30.3 and 22.4%

Degradation

 of lignin at 17.1%

Digestibility

 of glucan and xylan enhanced to 53.9 and 58.2%

Digestibility

 of glucan and xylan reached 54.8 and 78.0%

Glucan and xylan digestibility

 increased up to 59.2 and 82.1%

Removal of lignin reached 45.8%

N.S

 65%

22

 N.S 120

 N.S •

• Lignin and cellulose

biodegradation

 of 56.5 and 13.9% [24]

Reduction of lignin and cellulose up to 57.4 and 16.7%

N.S

 70%

25

 N.S 21

 N.S

• Loss of lignin at 16%, while both

5% each

• Lignin degradation cellulose of 9% individually

 of 16%, whereas

hemicellulose

 and [10]

hemicellulose

 and cellulose at

[14]

Fungal Pretreatment of Lignocellulosic Materials DOI: http://dx.doi.org/10.5772/intechopen.84239

Fungi

Inoculum

Moisture

T (°C) pH Time

species

conc.

content (%)

(days)

Nutrient

 Effect

•

Lignin, and 55%

> •

Removal of lignin,

39, 44 and 45%

hemicellulose

 and cellulose increased up to

hemicellulose

 and cellulose reduction reached 47, 39

References

#### Fungal Pretreatment of Lignocellulosic Materials DOI: http://dx.doi.org/10.5772/intechopen.84239


Substrate

46

Sugarcane bagasse P. ostreatus

Fungi

Inoculum

Moisture

T (°C) pH Time

species

conc.

0.05 w/w

N.S

27

 N.S 60

 + • • • •

Glucan and xylan digestibility

 increased up to 55 and 27%

Lignin, xylan and glucan removal at 48, 47 and 13.6%

Glucan and xylan digestibility

Lignin, xylan and glucan degradation

 up to 11.1, 15.7 and 8.4%

 reached 35 and 19%

%

C.

subvermispora

> Wheat straw

C.

10 w/w%

 70%

24

 N.S 56

 N.S •

Decrease in lignin,

and 20.2%

> •

Lignin, and 12.2%

hemicellulose

 and cellulose

biodegradation

 of 71.7, 69.3

[21]

hemicellulose

 and cellulose were 83.3, 80.5

[21]

Biomass for Bioenergy - Recent Trends and Future Challenges

subvermispora

L. edodes

> Oak wood chips

C.

10 w/w%

 70%

24

 N.S 56

 N.S •

Reduction of lignin,

50.6 and 17.4%

> •

Lignin, 56.3 and 37.3%

hemicellulose

 and cellulose removal increased to 60.6,

hemicellulose

 and cellulose content at 53.5,

subvermispora

L. edodes

> Willow sawdust

> A. biennis

0.32 w/w

80%

27

 N.S 30

—

•

Degradation

19.3 and 7.4%

> •

Lignin,

hemicellulose

 and cellulose loss of 30.5, 42.4 and 26.6%

 of lignin,

hemicellulose

 and cellulose reached 17.1,

[22]

%

L. menziesii

0.48 w/w

%

> Wheat straw

Corn stover

I. obliquus

8%

 N.S

28

 6 12

 + •

Decrease in lignin,

55%

hemicellulose

 and cellulose up to 72, 46 and

[23]

content (%)

(days)

Nutrient

 Effect

References

[18]

