Enzymatic Depolymerisation of Hemicellulose into Arabinose and Xylose by Aerobic Bacteria
Abstract
The cellulotic and hemicellutotic materials found in plant can be utilized for generating bio-fuel by breaking them into simple sugar form. The depolymerisation of hemicellulose has been investigated, since it is second highest sugar component after cellulose. Hemicellulolytic microorganisms were obtained by enrichment of samples taken from aerated composting piles essentially composed of lignocellulosic plant wastes. The isolated Microorganism demonstrated the appreciable hemicellulolytic activity in depolymerising hemicellulose into simple pento sugars under the favorable conditions. The extent of endoxylanase (107.76 IU/ml) and sugar (2088.81 µg/ml) were found to be produced in the present investigation.
Keywords
Download Options
Introduction
Increasing global energy necessities and greater environmental consciousness have resulted in increasing emphasis on alternatives to fossil fuels as energy sources. Lignocellulosic biomass such as agricultural residues, forestry waste and municipal solid waste are sustainable and renewable resources for the production of liquid biofuels such as bioethanol [1]. As most often being a by-product from food and feed production, lignocellulosic biomass does not compete with the production of edible crops [2, 3] and has the potential to be the feedstock for the production of a considerable proportion of transport fuels if cost effective conversion processes are available [4]. The major components in lignocellulosic biomass are cellulose, hemicellulose and lignin. Hemicellulose sugars are the second most lavish carbohydrates in nature and its transformation to ethanol could provide a substitute liquid fuel source for the future [5]. The carbohydrates and lignin make up a major portion of biomass sample, carbohydrates can be structural or non structural. During the hydrolysis the polymeric carbohydrates are hydrolysed into the monomeric forms, which are soluble hydrolysis liquid. They are then measured by HPLC. A measure of acetyl content is necessary for biomas containing hemicellulose with a xylan backbone, but also biomass containing a mannan backbone. Acetate is measured by HPLC [6]. The degradation of cellulose and hemicellulose is carried out by microorganisms that can be found either free in nature or as part of the digestive tract of higher animals. The variable structure and organization of hemicellulose require the intensive action of many enzymes for its complete degradation. In many niches, this process is very slow because of the insoluble rigid structure of the plant cell wall and the limited availability of efficient cellulolytic and hemicellulolytic microorganisms.
Many studies on cellulose have acknowledged cellulolytic bacteria as discussed above, but not many on hemicellulose which has been the historical dogma/backlash. In this study attempt is made to depolymerize the hemicellulose by using aerobic bacteria isolated from aerated compost.
Conclusion
The enzymatic conversion of carbon source, such as Xylan, extracted from beech wood into C5 sugars such as Arabinose and Xylose. The simultaneous conversion of high concentrations of xylanolytic enzymes isolated from aerated composting piles mainly composed of lignocellulosic plant wastes. The number of microorganism with hemicellulosic activity showed that it can grow and produce xylanolytic enzymes on simple compost waste sources such as lignocellulosic biomass.