AI Summary & Key Takeaways
AI InsightA modified form of the model equation used to describe the basic hydrolysis process gave a good fit the experimental data obtained.
📌 3 Key Takeaways
Abstract
Efficient cellulose hydrolysis remains one of the most challenging problems in attempting to convert cellulose wastes into fuels or chemicals, and pre-treatment has been found to be crucial step before enzymatic hydrolysis of these polymers can effectively take place. As a result various pre-treatment methods have been developed to facilitate these bio-conversion processes, and this research focuses on the effect of two pre-treatment methods such as low pressure steam and sulphuric acid pre-treatment to remove some of the components like lignin and hemicellulose which form structural barrier to enzymatic accessibility of cellulose in corn cobs and sawdust. The cellulosic materials were first dried in oven at 65oC for 24 hours, and using solid to liquid ratio of 1:10, the two methods were carried out at resident times ranging from 10 - 40 minutes. The low pressure steam method involved heating the cellulosic materials in an autoclave at 120oC and 1atm above the normal atmospheric pressure; for the second method, the dried cellulosic materials were refluxed in 5 % sulphuric acid at a temperature of 120oC. Pre-treated samples were filtered and liquid fractions were analysed for the presence of reducing sugars, while solid residues were dried in the oven and weighed to measure the mass lost during pre-treatment as a pointer to lignin breakdown. It was observed that the mass lost increased with time for both pre-treatment methods, but the low pressure steam pre-treatment gave higher lignin and hemicellulose removal when compared to the sulphuric acid pretreatment. The liquid fractions after pre-treatment were found to contain some reducing sugar which increased with pretreatment time and was higher in the corn prehydrolysate. The pre-treated materials were hydrolysed with two combinations of commercial enzymes namely cellulase/ hemicellulase and cellulase/? glucosidase. The reducing sugar was measured using Dinitrosalycilic acid (DNSA) method and the sugar yields from corn cobs were higher than that of sawdust when subjected to similar process conditions, and the enzyme combination of cellulase/glucosidase gave higher yields of reducing sugars. A modified form of the model equation used to describe the basic hydrolysis process gave a good fit the experimental data obtained.