Novel Nano Catalyst Ionic Liquid Assisted Pretreatment of Aloe vera Rinds and Delonix regia Pods: A Comparative Study

Purpose Globally, the demand for fossil fuels is a major issue that needs attention through replacement using bio resources. This work aims to carry out a comparative study on the production of biofuels from the rinds of Aloe vera and the pods of Delonix regia. Aloe vera rinds have several characteristics, like cellulose, vitamins, enzymes, sugars, lignin, saponins, etc. It was used as the lignocellulosic feedstock for bioethanol production due to the availability of cellulose and hemicellulose content, which can be hydrolyzed into fermentable sugars.Methods In this research, a physiochemical method employing ionic liquid-assisted nanocatalyst was performed. Pretreatment was carried out along with the application of ultrasound waves to extract the fermentable sugars. The ultrasonication time, concentration of ionic liquid, and nanocatalyst was optimized to extract the maximum amount of fermentable sugars. The ultrasound treatment was found to be efficient for 20 min. Musa acuminata peels was used to synthesize copper oxide nanoparticles (CuO NPs). The size and shape of the CuO NPs was studied by scanning electron microscopy (SEM) analysis. Pretreatment of the Aloe vera rinds and Delonix regia pod was performed using ionic liquid-assisted nanocatalysts separately and in combination with the ionic liquid (triethyl ammonium hydrogen sulfate) and CuO NPs.The combined pretreatment step using the ionic liquid and CuO NPs with ultrasound extraction revealed the highest concentrations of fermentable sugars of 0.3 mg/ml and 0.21 mg/ml for Aloe vera rinds and Delonix regia pods, respectively. High performance liquid chromatography (HPLC) analysis was carried out in the hydrolysates of the feedstock after pretreatment. The cellulose and hemicelluloses content was found to be 0.82% and 0.26% for Aloe vera rinds, 23.65% and 12.67% for Delonix regia pods. Di-nitro salicylic acid assay (DNSA) was performed to estimate the hydrolyzed sugars. Fermentation using Saccharomyces cerevisiae was carried out with the extracted sugars and its growth kinetics were studied. The ethanol produced was 1.01 mg/ml from Aloe vera rinds and 0.81 mg/ml from Delonix regia pods.Conclusion Thus, the combined pretreatment step increases the efficiency of extraction and the yield of fermentable sugars for bioethanol production.

Automated summary

This study conducted a comparative study on the production of biofuels from Aloe vera rinds and Delonix regia pods. The combined pretreatment step using ionic liquid-assisted nanocatalyst and ultrasound extraction was found to increase the efficiency of extraction and the yield of fermentable sugars for bioethanol production.