Effect of Potassium Hydroxide (KOH) Pretreatment on Solids Recovery, Delignification and Total Sugars of Cotton Stalk

Optimization of the autoclave-assisted alkaline delignification of cocoa (Theobroma cacao) pod husks using KOH to maximize reducing sugars

“…The solids recovery ranged from 55.6% to 80.2%, corresponding to tests 8 and 1, respectively. Similar values were obtained by Premkumari et al (2019) with cotton swab. They found solids recovery values between 51.7% and 82.9% for 2% KOH pretreatments at temperatures between 50 and 120 °C.…”

“…The main factors involved in the delignification process and their domains of variation were chosen on the basis of previous studies (Nazir et al 2016;Ghazanfar et al 2018;Premkumari et al 2019). A mass of cocoa pod husks was placed in a 250 mL flask, containing 100 mL of KOH with a concentration of between 1 and 5% w/v and according to the biomass to solvent ratio varying from 5 to 10% w/v, given by the design of the experimental design.…”

“…In a recent study, the orange peel was exposed to a conventional alkaline and ultrasonically assisted pretreatment at room temperature reaching 86% delignification and 92% delignification in 4 h respectively, with a maximum reducing sugars of 1.30 g/L in 6 h of treatment after enzymatic hydrolysis; compared to the conventional method where the sugar concentration was 0.814 g/L in 24 h (Utekar et al 2021). Likewise, the effect of KOH was evaluated on other substrates, for cotton swab (120 °C for 1 h with 3% KOH, giving 68.9%) of delignification (Premkumari et al 2019), corn straw (With conventional heating at 50°C for 24 h with 2% KOH, with 87.7%) of delignification (Dąbkowska-Susfał 2020).…”

“…However, the physicochemical and physical delignification processes are inefficient and biological delignification processes are expensive and can be time consuming. As such, chemical delignification processes are the most utilized type, and the alkaline delignification in particular has met with considerable success (Premkumari et al 2019). Delignification using alkalis can efficiently and selectively remove lignins, thus increasing the digestibility of cellulose.…”