**3.1 Hydrolases**

The group of hydrolases enzyme includes amylases, cellulases, pectinases, proteases and lipases. In addition, hydrolases enzymes mainly act as hydrolysis. For isolating microbial strains that produce the desired enzyme and optimizing the conditions for growth, commercial quantities can be obtained. This technique, well known for more than 3,000 years is called fermentation [8].


**Table 2.**

*Classification of enzyme based on textile applications.*

#### *3.1.1 Amylases*

Amylases hydrolyze starch molecules to give dextrins and maltose, which composed of glucose units [22]. The various starch-splitting enzymes are known as αamylases and β-amylases [23] (**Figure 2**).

α-amylases are produced from different fungi, yeasts and bacteria. The different microorganisms from α-amylases are listed in **Table 3**.

α-amylases are quite stable over a wide range of pH from 4 to 11. Optimum temperature for the activity of α-amylases is usually applied for modified microorganism. Addition of Ca2+ cans enhances thermo stability [24].

Commercial desizing compound under name Rhozyme DX, Rhozyme GC, Diastafor LCD (Bacterial α-Amylases) is more suitable for desizing compared to β-amylase from crude Barley & amyloglucosidase from (*Rhiszopus genus mold*) [25]. Amylase obtained from cheap waste animal pancreas are efficient in desizing for exhaust and pad batch application [26]. Microbial α- Amylase obtained from *Bacillus amyloliquefaciens* performed 100% desizing efficiency with pH 6.5 & 60<sup>o</sup> C for 1 hour [27]. α- Amylase obtained from *Aspergillus niger* sp. MK 07concentration of 300 U/ml performed at 75<sup>o</sup> C, pH 6.5 with 0.3 M CaCl2 [28]. Glucoamylase (Multifect GA 10 L) and α- Amylase (Optisize Next) enzymes mixed with chelating agent in citric acid perform simultaneous acid-demineralization and desizing [29]. Ultrasound assisted α-amylase save half desizing process time [30] and α-amylase in winch machine performs highest desizing quality [31]. Ca2+ ion independent α-Amylase (*Bacillus sp. KR8104*) activate at moderate temperature (30-70<sup>o</sup> ) desizing with acid-demineralization possible under acidic condition, presence of salts could

#### **Figure 2.**

*Degradation of starch by α-amylases and β-amylases.*


**Table 3.**

*α-amylase from different microorganisms.*

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

decrease enzyme dosage and process time [32]. Amylase obtained from *Aspergillus niger & Aspergillus flavus* shows higher desizing efficiency (*A. niger 96%, A. flavus 90%*) with significant improvement in absorbency & extractable impurities [33]. α- Amylase (*Bacillus sp. KR 8104*) shows simultaneous enzyme production and desizing optimized using inexpensive raw materials for α- Amylase [34]. Amylase assisted with other enzyme like *Aquazym* amylase & Lipase improve starch removal and shorten desizing time [35]. α-Amylase (*Aquazym*) incorporate of H2O2 or neutral cellulase improves desizing with whiteness and dye-ability presence of wetting agent governed extent of desizing [36]. Alkaline amylase (commercial enzyme Novozymes) performs both desizing & bio-scouring in single bath [37]. Polygalacturonase (*Trichoderma harzianum*) optimize combined pre-treatment in terms of weight loss, residual starch %, absorbency, strength loss and copper number [38]. Thermophile α-Amylase obtained from *Bacilluslicheniformis* optimizes cotton desizing using 3 g/l acidic with 6 pH at 85<sup>o</sup> C for 40 min [39]. α-Amylase obtained from *mesophilic* shows thermal stability in various additives for high temperature desizing, chitosan saves 2/3 enzyme dosage & improve desizing effect [40]. Amylase from *Aspergillus niger* immobilize with alkylamine glass beads are effective for removal of starch stains along with various detergents [41]. α-Amylase from soyabean seeds entrapped in agarose and agar matrices with 75% & 77% activity reused up to 5 cycles in starch stain removal [42].
