Table 4.
Degradation methods and their application.
| Degradation Type | Treatment | Experimental Method | Ref. |
|---|---|---|---|
| Mechanical, enzymatic degradation | Ultrasound, cellulose | Ultrasound with 38 KHz; 50 mg cellulase per liter; pH range 4.8–5.5; 0.1 mol NaOH or 0.1 mol HCl and 2 g powdered crystalline cellulose. | [149] |
| Mechanical, thermal degradation | Defibrillation, lyophilization degradation | Defibrillated in a super mass colloid with 4.5 wt% distilled water for 5 h at a speed of 1500 rpm; frozen at −80 °C; lyophilized at −40 °C for 3 days | [150] |
| Mechanical, thermal degradation | Freeze-dried, air-dried dehydration, themo-oxidation | pH = 4.518 prior to freeze drying. 15 mg sample under air and nitrogen at heating rates of 1, 3, 5, 10, 15, 20, 30, 40, 50, 75, and 100 °C/min between 25 and 800 °C | [151] |
| Photocatalytic degradation | Nano-Graphene Oxide-Type | CA (30 mg/mL) and 2.5 wt% carbon dots in 5 mL acetone; ultrasonic bath dried in an oven at 80 °C; 50 °C with 370 nm UV light irradiation | [152] |
| Chemical, enzyme degradation | Chitinase, cellobiohydrolase | Using 100 mg of each substrate; 5 mg of the different substrate; pH = 6 with 20 μL of 10 mM gallic acid and 5 μL enzyme; 25 °C, 900 rmp in the dark, covered with an O2 permeable foil for 145 h. | |
| Bacteria, enzyme degradation | Beta-glucosidases of cytophaga hutchinsonii | E. coli strains cultivated in medium supplemented with 0.2% (wt/vol) glucose; 0.2% (wt/vol) cellbiose; cells were grown with 0.2% (wt/vol) glucose at 30 °C with antibiotics. | [153] |
| Chemical degradation | Glucose; DMSO; copper (II) ethylene diamine solution | 4 wt% cellulose with dissolution temperatures were varied from 90, 100, 110, 120, 130 °C within 72 h; then dried. | [154] |
| Thermal degradation | Drying; alkali; heat | 10 mg of extracted sample was heated from 25 to 600 °C at different heating rate of 3 °C/min, 7 °C/min, 11 °C/min, and 15 °C/min | [155] |
| Hydrothermal degradation | Hydrothermal; acid | 3.5 g NaOH, 0.3 g ZnO and 46.2 g deionized water with a solvent (1.75 mol/L NaOH/0.074 mol/L ZnO) stirred; take 2 mg of cellulose solution into 100 mL stainless steel autoclave. | [156] |
| Alkaline hydrothermal degradation | Hydrothermal; alkaline | 3 g NaOH, 1 g urea, and 45 g deionized water were added into a flask and stirring at 4 °C for 2 h. 0.2–2.5 microcrystalline cellulose was added under stirring. −20 °C for 12 h. They were then thawed and added into an autoclave. | [157,158] |
| Bacterial degradation | Citrobacter freundii | Microcrystalline cellulose 5 g were added into minimal medium consisting of 2 g/L Na2HPO4, 1.32 g/L KH2PO4, 1 g/L NH4Cl, and Citrobacter freundii, etc. | [159] |