Nanocrystalline cellulose from lactic acid hydrolysis of pepper waste (Piper nigrum L.): Response surface methodology optimization and application in bio-composite

Nanocrystalline cellulose (NCs) was successfully isolated from pepper biowaste using lactic acid hydrolysis and employed as filler in seaweed biocomposite. Optimization of hydrolysis parameters by employing response surface methodology (RSM) generates 75.50 % NCs with 76.68 % crystallinity at 6.31 M lactic acid, 3.02 h and 85.86 °C. The ANOVA analysis indicates hydrolysis efficiency requires precise temperature control and lactic acid concentration to obtain high crystalline cellulose at high production yield. The NCs displayed rod-shaped morphology with 29.65 ± 3 nm diameter and 335.19 ± 10 nm length, with a negative zeta potential and higher thermal stability than the cellulose. NCs addition as filler in seaweed biofilm improved the tensile strength but reduced the elongation at break. The biofilm exhibits excellent properties in reducing water adsorption, solubility, and water permeability by increasing nanocellulose filler.