Surfactant-modified magnetic CaFe-layered double hydroxide for improving enzymatic saccharification and ethanol production of Artemisia ordosica

The utilization of bio-surfactant rhamnolipid (RL) modified magnetic CaFe-layered double hydroxides (RL-LDH) was successfully carried out to enhance the enzymatic saccharification and ethanol production of Artemisia ordosica (AO). The RL-LDH pretreatment could effectively improve enzymatic hydrolysis of AO. The ethanol yield reached 167.4 mg/g (the reducing sugar yield achieved 540.3 mg/g) when pretreatment pH was 9, RL-LDH to AO mass ratio was 1.5:1, pretreatment time was 1 h, enzymatic hydrolysis temperature was 50 °C, cellulase loading was 50 FPU/g, and simultaneous saccharification and fermentation (SSF) time was 120 h. RL-LDH could stabilize the enzymes and yeast, resulting in increased the reducing sugar and ethanol yields and decreased conversion costs of biofuel. Furthermore, the conversion yields were still higher than that of control group (without RL-LDH) after the RL-LDH was used for 5 times repeatedly. Therefore, utilization of recyclable RL-LDH is promising for future applications in enzymatic hydrolysis and fuel conversion of biomass.