Lignocellulosic Properties of Coffee Pulp Waste After Alkaline Hydrogen Peroxide Treatment

Abstract

The effect of alkaline hydrogen peroxide (AHP) treatment on reducing lignin content in coffee pulp waste (CPW) was investigated to increase the digestibility and accessibility of cellulose during production of valuable products by enzymatic and biological process. Hydrogen peroxide (H2O2) at various concentrations (2.5, 5, and 7.5% (w/w of substrate)) was mixed into 10% (w/v) of CPW-NaOH solution at 35 °C for 24 h with pH 11.5. The concentration of lignocellulosic content was investigated. The characteristic of crystallinity index, functional groups, and surface morphology of CPW at before and after the treatment have been observed using XRD, FTIR, and SEM analysis, respectively. The results showed that the highest lignin removal was achieved at the addition of 7.5% H2O2 which decreased from 16.85% to 8.5%. The concentration of cellulose and hemicellulose in CPW increased from 53% to 64% and 11% to 24%, respectively. The crystallinity index of AHP-treated CPW has increased from 30.83% to 42.08%. A surface morphological destruction on the CPW was getting worse as along with the increase of H2O2 concentration. This would be useful to increase the porosity of biomass to give cellulose accessibility by enzyme for further processes.

Alkaline delignification of lignocellulosic biomass for the production of fermentable sugar syrups

“…kikuyo grass, sugarcane bagasse) showed damage in their structure which included rupture of cell walls, exposing inner parts, as well as increasing the surface area and making them more accessible to subsequent hydrolysis. These observations agree with reported results from other studies [1,7,10]. As seen, pretreated African oil palm fiber (Fig 2d-2) exhibited a rough surface due to the orientation changing of highly packed crystalline cellulose order to form an amorphous region, which allowed the OH group to break down to react with water molecules and then leave the fiber structure.…”

“…The sample preparation for analysis and extraction procedures were performed according to the Laboratory Analytical Procedure, NREL [45]. All determinations were conducted by duplicate [7]. Reported data in tables and figures correspond to average values with a relative standard deviation of less than 5%.…”

“…Alkaline pretreatment is considered an effective chemical pretreatment for the delignification of agricultural wastes [10,2,17]. Among the desirable features, it can operate under mild temperature and pressure conditions with minimal sugar degradation and without the formation of inhibitory compounds, solubilizing mainly lignin to enhance the cellulose content and improving carbohydrate digestibility [1,7,9,15,18]. Non-polluting and non-corrosive reagents such as ammonia, sodium hydroxide, sodium carbonate, and calcium hydroxide are used.…”

Delignification of Cassava Peel by Using Alkaline Hydrogen Peroxide Method: Study of Peroxide Concentration, Solid/Liquid Ratio, and pH

“…By means agricultural waste has different optimum conditions. Pudjiastuti [30] studied the effect of H2O2 concentration in the coffee pulp waste pretreatment using AHP. The research result showed that the highest lignin removal was achieved by adding 7.50% H2O2.…”

Coffee Pulp: An Industrial By-product with Uses in Agriculture, Nutrition and Biotechnology

“…In addition, white rot fungi such as Sporotrichum pulverulentum and Stropharia rugosoannulata showed a low lignin solid residue with the same enzymatic digestibility as that found for the original coffee pulp. Other studies report that alkaline hydrogen peroxide (AHP) treatment of coffee pulp residue results in a reduction of lignin content; and thus leads to increased digestibility of cellulose (Pudjiastuti et al, 2019).…”