Effect of Acid and Base Pre-Treatment on Enzymatic Hydrolysis of Desmostachya bipinnata (Daabh)

https://doi.org/10.5281/zenodo.17863413

Abstract

The transformation of lignocellulosic biomass to fermentable sugars in an efficient manner is also a key aspect of challenge in biofuel production in the second generation. This paper examines the relative opportunities of acid and base pre-treatment of the enzymatic hydrolysis of Desmostachyabipinnata(Daabh) which is a salty halophytic grass common in South Asia and can grow in both salty and marginal soils. The fractions were diluted with sulfuric acid (1.5 percent w/v, 2.0 percent w/v and 2.5 percent w/ v) and sodium hydroxide ( 1 percent w/v, 1.25 percent w/v and 1.5 percent w/ v) and incubated at 100 o C in 15, 30 and 60 minutes to assess the best delignification and hemicellulose solubilization conditions. The amounts of reducing sugars were measured by 3, 5-dinitrosalicylic acid (DNS) assay, and enzymatic hydrolysis of the cellulose under controlled conditions (55C, 24h) was used to test the presence of cellulase produced by Aspergillus niger. It was found that 2.5% H 2 SO 4 30 minutes gave the highest acid pre-treatment yield (84.44%), and 1% NaOH 60 minutes gave the highest yield of base (94.26-percent). Enzymatic hydrolysis, after-facto, showed the total saccharification yields of 90.94 and 96.48% of acid and base-treated biomass, respectively, providing support to the high productivity of alkaline delignification in improving the access section of the enzymes. The experiment provides evidence that mild NaOH pre-treatment is superior to acid hydrolysis to break down the recalcitrant lignocellulosic skeleton of the D. bipinnata which makes the plant a promising feedstock in the generation of bioethanol at large scale in arid and salty conditions that require no food to grow.