*3.1.2 Cellulases*

Cellulases are hydrolytic enzymes that breakdown the cellulose to form oligosaccharides and finally glucose. Cellulase combining at least three types of enzyme for working synergistically on cotton (**Figure 3**).

The length of cellulose chains cleaves endogluconases or endocellulases in the middle of the amorphous region. However, exo-cellulases start their action from the crystalline ends of cellulose chains and convert to glucose by β-4-glucosidase [43]. These enzymes are commonly produced by soil-dwelling fungi and bacteria (**Table 4**).

A temperature range from 30 to 60o C is an active condition for cellulase. According to pH sensitivity, cellulase enzymes are classified in different categories

**Figure 3.**

*Degradation of cellulose by cellulase enzyme*


**Table 4.**

*Cellulase enzyme from different microorganisms.*

such as acid stable (pH 4.5–5.5), neutral (pH 6.6–7) or alkali stable (pH 9–10) [44]. Cellulase obtained from *Denimax L*& Pectinase (Pectinex USP) Novo Nordisk, V1– 4 Xylanase (*Bacillus sp.*) optimized bio-polishing of jute-cotton blended fabrics for fuzz removal [45]. Cellulase, Endo-enriched cellulase, Exo-endo mixed cellulase are best suited for cotton and lyocell fabric especially for cotton, knits, linen and rayon [46]. Ecostone L883042 and Denimax L used for desorption the cellulase from cotton using ultra filtration for recovering and recycling [47]. Commercial cellulase like Gempil 4 L used for ring spun colored knitted fabrics for pill and fuzz removal [48]. G-ZYME VGB ST trade mark from Rossari are very useful for the action of cellulases on reactive dyed cotton and also show very good effect of bio-polishing on various spun yarn knitted fabrics [49, 50]. On the other hand, Acid cellulase from Genencor, USA performed better enzymatic hydrolysis on viscose, lyocell, modal &cotton fabrics were examined in-terms of degradation rate and weight loss [51]. Acid cellulase obtained from *Talaromyces emersonii* are thermostable cellulase obtained & applied for jute-based fabrics finishing to exhibit improved lusture, handle and durable softness [52]. Commercial cellulase Biopolish EC used for combined scouring-bleaching by cellulase treatment for knit fabrics [53]. Cellulase from *Trichoderma Vride G* optimizes cotton fabric for bio-polishing to improve its smoothness with minimum weight loss [54]. Indiage44L (Gencor) complex with mixed cellulase act as bio-scouring followed by bleaching either peroxide or peracetic acid is efficient for towels and endoglucanase is effective instead of cellulase as additive for terry towel washing [55]. Cellulase from *Trichoderma reesei* performed cotton bio-polishing & its effect on the morphologies [56]. Cellulase from *Chaetomium globosum* performed cotton bio-polishing in-terms of breaking strength, weight loss, thickness, drape and abrasion resistance [57]. Cellulase from *Aspergillus niger* immobilized on maleic anhydride modified PVA coated chitosan beads improves stability of acidic cellulase in neutral pH range [58]. Endoglucanase II (*Trichoderma reesei*) is effective for removing color from denim, producing a good stonewashing effect with lowest hydrolysis level [59].

Alkali Cellulase (*Alkalothermophilic Thermomonospora sp.*) are first time alkali stable endoglucanase used for bio-polishing denims, provide abrasive effect and softness with lower backstaning& negligible weight loss [60]. Cellulase from *Hypocrea jecorina* with nonionic surfactant and dispersing agents provide double benefits of reduction in backstaning and increased cellulase activity [61].

Suhong 89 from Acid cellulase efficiently removes indigo from denim surface with minimum hydrolysis & possibility of cellulase reuse [62].

#### *3.1.3 Pectinases*

Pectinase are complex enzymatic group that degrade the pectic substances. They are produced from saprophytes and plant pathogens which can degrade the plant cell walls. There are three major classes of pectin degrading enzymes are pectin esterases, polygalacturonases and polygalacturonate lyases [63].

Pectin Esterases: Pectin esterases liberate pectin and methanol by de-esterifying the methyl ester. Their activity is highest on 65–75% methylated pectin, is to act on methoxy group adjacent to free carboxyl group. Its action has very little effect on the molecular weight of the pectin (**Figure 4**).

Pectin esterases active in the pH range of 4–8 and optimal temperature range for maximum activity is 40-50<sup>o</sup> C.

Polygalacturonases: Polygalacturonases reduce the molecular weight of the pectins. They catalyze the hydrolytic cleavage with the introduction of water across the oxygen. They are classified further as endo-galacturonases and exo-galacturonases (**Figure 5**).

*Sustainable Textile Processing by Enzyme Applications DOI: http://dx.doi.org/10.5772/intechopen.97198*

**Figure 4.**

*Degradation of pectin by pectin esterases.*

#### **Figure 5.**

*Degradation of pectin by polygalacturonases.*

Polygalacturonases obtained from different natural sources with respect to physiochemical and biological properties as well as their mode of actions.

Pectin Lyases: Pectin lyases depolymerise the pectin. These catalyse the transeliminative cleavage of the galacturonic acid polymer. It can break down the glycosidic linkages at C-4 and eliminate H from C-5 position (**Figure 6**).

Pectin esterases, polygalacturonases and pectin lyases are mainly produced in plants such as banana, citrus fruits and tomato, but also by bacteria and fungi (**Table 5**).

Bioprep 3000 L, Novozyme acts as alkaline pectinase are efficiently remove impurities formed uniform dyeing consistency & equivalent color depth with different direct dyes [64]. Pectinase from *Aspergillus niger* named as Bioprep 3000 L agitate improve efficiency and optimize enzymatic scouring provide less damage & superior fabric quality [65, 66]. Bioprep 3000 L Pect062L, Biocatalyst (Acid Pectinase) performs both acid and alkali pectinase are equally efficient but acid pectinase works with lower concentration [67]. Bioprep 3000 L scoured cotton knit fabric at 80<sup>o</sup> C for removing wax and higher dye uptake optimize bio-scouring for

**Figure 6.**

*Degradation of pectin-by-pectin lyases.*


#### **Table 5.**

*Pectinase enzyme from different microorganisms.*

physical, chemical & low stress mechanical properties [68]. Pectinase obtained from *B.macerans* strain V-2692 contains cellulose & hemi-cellulase remove pectin but improve fabric capillary much greater which can substitute cotton boil-off [69]. Multifect cellulose GC obtained from *Trichoderma longibrachiatum* and Multifect pectinase PL from *Aspergillus niger* synergism of cellulose efficiency removes pectin and protein, mechanical agitation and compatible surfactants also play important role [70]. Viscozyme 120 L (Pectinase + hemicellulose) treatment prior to alkaline scouring along with chelating agent at acidic pH, efficiently lightens the seed-coat fragments to improve whiteness and gives better results of wet ability, pectin removal and dyeing with 60 min treatment time [71]. Pectinase, lipase and cellulase enzyme combinedly perform successful scouring, dye and water absorbency with some fiber damage [72]. Alkaline Pectinase (*Bacilus*), Acidic pectinase (Microorganism) along with neutral cellulose (*Apergillus aculeatus*) performs best in wax removal & high absorbency [73]. Alkali Pectinase & Cellulase combinedly scoured knitted fabrics in two step one bath process [74]. Bioprep 3000 L Alkali Pectinase (*Bacillus sp.*) & Lipolase 100 L (*T. lanuginosus*) combined lipase in one-step reduce time required & fabrics with superior properties and excellent dyeing performance obtained [75]. Xylanase from *Bacillus pumilus* are thermostable enzyme provide simultaneous desizing and scouring, addition of chelating & wetting agent increases hydrolysis and allowed reduction of H2O2 consumption in consecutive bleaching [76]. Bioprep 3000 L and Forylase KP. Cognis (Acidic Pectinase) simultaneous scouring & bleaching using Pectinase & PAA sufficiently remove pectin and wax to achieve excellent absorbance with medium degree whiteness without damaging fiber and good dye-ability with less energy & water use in enzymatic and/or PAA treatments because of 60<sup>o</sup> C & pH 6–8 [77–79].

#### *3.1.3.1 Proteases*

Proteolytic enzymes produced by microorganisms are mixtures of endopeptidases and exopeptidases. The simplified form the action of the proteases are (**Figure 7**).

Microbial proteases obtained from the plant source such as papain, ficin, and the animal proteases obtained from pepsin and trypsin. Microbial proteolytic enzymes obtained from different fungi and bacteria. Most fungal proteases activate in a pH range (about 4 to 8), and bacterial proteases generally work best over a range of about pH 7 to 8 [80] (**Table 6**).

Proteases with cellulase (Commercial Enzyme) mixture perform for bioscouring and optimized using ANN technique to achieve desired absorbency and pectin removal [81]. Proteases (*Bacillus*) and cellulase provide successful scouring, dye, and water absorbency with some fiber damage in presence of cellulase [82].
