The accumulation of pith in a coconut husk processing facility leads to disposal problems, fire hazards, and contamination of groundwater. The leachate contains phenolic compounds that percolate through the soil and contaminate groundwater. Monolignols (guaiacyl (G), syringyl (S), and p-hydroxyphenyl (H)) in soil and groundwater pose a threat to the land and water resources. This study focuses on minimizing waste accumulation by treating the accumulated pith with sodium hydroxide to recover lignin and sugar. Pith, which has about with 24% cellulose and 49% lignin, was used as a substrate for recovery of Kraft lignin (KL) and sugar. The operating condition for the recovery of KL was optimized using response surface methodology (RSM). Maximum KL recovery (~ 86%) was achieved with optimal biomass loading of 65 mg/ml, NaOH concentration 5.12% w/w, residence time 31 min, and temperature 121 °C. A glucose yield of 95% was obtained after 48 h of saccharification. The removal of the aromatic layer increased the crystallinity index (CrI) after hydrolysis from 65 to 81.7%. The S/G ratio of 0.49 indicated that the lignin structure of pith is a matrix with many branches, thus making the lignin matrix strong and rigid.

Graphical abstract

髓在椰子壳加工设施中的积累会导致处置问题，火灾隐患和地下水污染。渗滤液中的酚类化合物会渗入土壤并污染地下水。土壤和地下水中的单木质酚（愈创木酚（G），丁香基（S）和对羟基苯基（H））对土地和水资源构成威胁。这项研究的重点是通过用氢氧化钠处理积累的髓以回收木质素和糖来最大程度地减少废物的积累。含有约24％纤维素和49％木质素的Pith用作回收牛皮纸木质素（KL）和糖的底物。使用响应面方法（RSM）优化了KL的恢复操作条件。最佳的生物量为65 mg / ml，NaOH浓度为5.12％w / w，可实现最大的KL回收率（〜86％），停留时间31分钟，温度121°C。糖化48小时后，可获得95％的葡萄糖产率。芳香层的去除将水解后的结晶度指数（CrI）从65提高到81.7％。S / G比为0.49，表明髓的木质素结构是具有许多分支的基质，因此使木质素基质坚固和刚性。

图形概要