Microwave Assisted Enzymatic Hydrolysis of Corn Stalks for L-lactic Acid Production

摘要

Glucose production from pretreated corn stalks by cellulose enzymatic hydrolysis with cellulase was investigated and compared with no pretreatment,as a reference.The corn stalks were pretreated with microwave,sulfuric acid hydrolysis and dilute sodium hydroxide solution hydrolysis respectively.The enzymatic hydrolysis experiments were carried out at 50°C,50 g/1 dry matter (DM) solid substrate concentration and 15 filter paper unit (IU)/g DM of a commercial cellulase.Fermentable sugar was able to be produced from all the pretreated corn stalks with an overall yield of 29-58% of the maximum theoretical yield,based on the glucan available in the solid and liquid substrate.The corn stalks pretreated with dilute acid had the best glucose yield as 58.09% followed by the corn stalks pretreated with acid and microwave with an overall yield of 57.02% with 15 IU/g DM of cellulase.Glucose was the main product with enzymatic hydrolysis yield ratio 38.89%in the dilute sulfuric acid pretreated corn stalks,while with enzymatic hydrolysis yield ratio 51.07%in the dilute sodium hydroxide solution and microwave pretreated corn stalks under enzymatic hydrolysis conditions.These advantages,along with their negative price,make these solids a valuable raw material for L-lactic acid production.