The alkaline process involves soaking the biomass in alkaline solutions and mixing it at a target temperature for a certain amount of time. A neutralizing step to remove lignin and inhibitors is required before enzymatic hydrolysis. Does any one tell me what is the procedure of this neutralization step and how it is carried out in case of NaOH pretreatment? What chemical is used for this process?
Dear Muhammad
I am delighted as you are working in enzyme technology area. In alkaline pretreatment of lino-cellulose, low concentration of NaOH is recommended. Your chance for enzymatic hydrolysis would be adjusting pH or neutralizing the alkaline condition. Use of thermo-alkaline and amylolytic enzyme generating bacteria can be an alternative for mild alkaline condition to carry out simultaneously enzyme reaction. As you generation enzyme at the same time enzymes are involved in amylotylic reaction. As a results mono-saccharides are formed. Otherwise use of mineral acids for small amount may help you for pH control and adjustments. If you wish to grow microorganisms for synthesis of alpha-amylase; then use of phosphate solution is desired to adjust pH. I would recommend after soaking wheat straw in alkaline solution, remove solid from the solution; then wash it out without any chemical carry out enzyme reaction.
Dear Muhammad,
During the pretreatment xylan is solubilised predominately in the form of oligomers, which are known to be highly inhibitory to enzyme. Better way to remove lignin and sugar degradation products and xylose oligomers.
Dear Ramesh, What is the procedure to remove lignin, sugar degradation products and xylan oligomers?
We use alkaline pretreatment (ammonia, sodium hydroxide, sodium carbonate) in our experiments. All the samples irrespective of treatment reagent have been cold water washed after the pretreatment. After pretreatment, the reactors were immediately removed from the oven and quenched to room temperature in water bath. The cooled slurry was vacuum filtered immediately through a filter paper (Whatman®, Grade 802 Fluted, size 32.0 cm). You can use the similar filter paper, if not same. The vacuum filtered wet solids underwent further washing using tap water until pH reaches approximately 7. After the filtration solids have to be collected carefully from the filter paper and measure the moisture content immediately. By doing that you can calculate the solids remaining after the free treatment. Apparatus needed are Büchner funnel, vacuum filtration flask. filter paper, vacuum pump.
Regards
Ramesh