Researchers experimented with using different concentrations of NaOH solution to pretreat corn stalks for biogas production. They found that pretreating with 4 mg·g-1NaOH resulted in a stable pH and increased biogas production by 4.5 times compared to untreated stalks. The pretreated stalks had a rough and porous surface, making it easier for anaerobic microbes to break down the material. This method is cost-effective and efficient for producing biogas from corn stalks.