## 6 Agro-Industrial Food Waste for Nanocellulose Production
### Production of Nanocellulose from Common Agro-Food Wastes  
A number of commonly generated agro-industrial food wastes have been employed by different researchers to extract cellulose and nanocellulose, using a range of pretreatment technologies. [PERSON] et al. [137] produced NC from walnut shells (WSs) using 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO; (CH\({}_{2}\))\({}_{3}\)(CMe\({}_{2}\))\({}_{2}\)NO) oxidation and the sulfuric acid hydrolysis method. The cellulosic fraction was extracted using NaOH, followed by bleaching. WS biomass was pretreated using 2% NaOH at a solid-to-liquid loading of 10 g/100 mL, and pretreatment was carried out for 4 h at 100 \({}^{\circ}\)C under constant stirring. TEM analysis revealed that the NC produced via TEMPO oxidation was irregular-block in shape, whereas sulfuric acid NC was 55-82 nm in length and 49-81 nm in width [137]. In another study, the production of NC from pineapple leaves was demonstrated. Pineapple leaf biomass was first pretreated using 4% NaOH at 80 \({}^{\circ}\)C for 2 h, followed by bleaching. The CNC from alkali-pretreated pineapple leaves was extracted using 64% (\(w/w\)) sulfuric acid (10 mL) at 45 \({}^{\circ}\)C for 60 min. The CNC produced was rod-like in structure, about 100-150 nm in diameter and 3-5 nm in length, and was successfully utilized as reinforcing fillers in natural rubber (NR) composites [138]. CNC production was also carried out from Vietnamese agricultural wastes (Nypa Fruitcans trunk, coconut husk fiber, and rice husk). The biomasses dispersed in distilled water were heated at 100 \({}^{\circ}\)C for 2 h for the removal of impurities, followed by oven-drying. The biomasses were then pretreated with 90% HCOOH at 100 \({}^{\circ}\)C for 2 h under a magnetic agitator in the circulation system. The hemicellulose content was removed by dispersing biomasses in a mixed solvent of formic acid, hydrogen peroxide and distilled water (90:4:6% \(w/w\), respectively) at 80 \({}^{\circ}\)C for 2 h, followed by filtration and washing using formic acid (80%) and distilled water. The CNC was produced using 64% sulfuric acid solution at 45 \({}^{\circ}\)C for 30 min with a strong agitation in the circulation system. The length and width of the CNC obtained was 200-500 nm and 10-15 nm, respectively [139]. Table 2 also lists some other agro-industrial food wastes which have been reported for the production of NC. For the sustainable production of NC from LB, it is necessary for a waste biomass to be abundantly present, easily transported from the fields of the industry for processing, and it must be rich in cellulose content that is considered a precursor for NC.  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Age-Individual Focal Waste** & **Cellular Content** & **Environment Condition** & **Method of NC Reduction** & **Type of NC** & **Dimensions** & **Reference** \\ \hline Two-task & 35.01\% & 1H(0)- and 1H-x solution (1:1) 60 \% C, 2.4h & Acid hydrolysis using & NCC & Width + 4.8\%m & [44] \\ \hline Rice stamer & 36.5 \(\pm\) 2.1\% & Multistep partitioning(0); N-Modt 4.00 \% C, 2.4h & Autonomous & CNF & Densumer + 14.7 \(\pm\) 7.0 nm & [44] \\ \hline Rice stamer & 36.5 \(\pm\) 2.1\% & Multistep partitioning(0); N-Modt 4.00 \% C, 2.4h & Autonomous & CNF & Densumer + 14.7 \(\pm\) 7.0 nm & [44] \\ \hline Mackheimer & 36.5 \(\pm\) 2.1\% & Multistep partitioning(0); N-Modt 4.00 \% C, 2.4h & Autonomous & CNF & Densumer + 19 \(\pm\) 5.0 nm & [44] \\ \hline Rice stamer & 36.5 \(\pm\) 2.1\% & N-Modt 4.00 \% C, 2.4h & Autonomous & CNF & Densumer + 1