Integrated alkaline delignification and enzymatic hydrolysis of durian peel: A promising route for sustainable cellulosic sugars production

Durian peel is an underutilized solid waste with low biodegradability, leading to its accumulation and pollution of the environment.This waste has been reported to contain 55.3% cellulose and 23.11% lignin.The cellulose possesses significant potential to be converted into glucose through hydrolysis, as cellulose is a polysaccharide comprising glucose monomers.However, the high lignin content hinders enzyme access to cellulose, necessitating delignification to improve glucose yield.Therefore, this study aims to investigate the synergistic effects of sodium hydroxide (NaOH) concentration and enzyme concentration on hydrolysis during glucose production.The presence of lignin that inhibited hydrolysis was removed through delignification involving NaOH as a catalyst at various concentrations and reaction times.Lignin content was analyzed using the SNI 0492: 2008 method, while cellulose was analyzed with the SNI 0444: 2009 method.The results showed that 6% NaOH used for 105 minutes was able to concentrate cellulose up to 81.31% and remove lignin by 95.67%.The reducing sugar concentration was analyzed with a sugar refractometer.The results also showed that concentrated cellulose was converted to 122 g/L reducing sugar with the addition of 1.25% (% v/w) cellulose enzyme for 48 h at 40 °C.