Improvement of Enzymatic Saccharification and Ethanol Production from Rice Straw Using Recycled Ionic Liquid: The Effect of Anti-Solvent Mixture

Abstract

One of the major concerns for utilizing ionic liquid on an industrial scale is the cost involved in the production. Despite its proven pretreatment efficiency, expenses involved in its usage hinder its utilization. A better way to tackle this limitation could be overcome by studying the recyclability of ionic liquid. The current study has applied the Box–Behnken design (BBD) to optimize the pretreatment condition of rice straw through the usage of 1-ethyl-3-methylimidazolium acetate (EMIM-Ac) as an ionic liquid. The model predicted the operation condition with 5% solid loading at 128.4 °C for 71.83 min as an optimum pretreatment condition. Under the optimized pretreatment condition, the necessity of the best anti-solvent was evaluated among water, acetone methanol, and their combinations. The study revealed that pure methanol is the suitable choice of anti-solvent, enhancing the highest sugar yield. Recyclability of EMIM-Ac coupled with anti-solvent was conducted up to five recycles following the predicted pretreatment condition. Fermentation studies evaluated the efficacy of recycled EMIM-Ac for ethanol production with 89% more ethanol production than the untreated rice straw even after five recycles. This study demonstrates the potential of recycled ionic liquid in ethanol production, thereby reducing the production cost at the industrial level.

Analysis of Single-Step Pretreatments for Lignocellulosic Platform Isolation as the Basis of Biorefinery Design

“…Expensive reagents characterize the ionic liquid process, and its recirculation is crucial. To reduce the OpEx in the ionic liquid schemes, recirculation of the ionic liquid was proposed by adding anti-solvent to the reactive mixture in a 1:1 by weight ratio followed by centrifugation and evaporation to remove the anti-solvent from the ionic liquid for its subsequent recirculation [ 68 ]. This process allowed more than 10% decrease in OpEx associated with the demand for reagents.…”

Investigation of a robust pretreatment technique based on ultrasound-assisted, cost-effective ionic liquid for enhancing saccharification and bioethanol production from wheat straw

“…The recycling capacity of the IL can help reduce the cost of the pretreatment. The low volatility of IL makes it feasible for recycling studies 26 .…”

“…Further, besides the use of inexpensive ILs with a considerable amount of water, biomass loading is utilized, being an important and economically justified parameter for the process. The acceptable rate of biomass loading is 10% in the literature 24 – 26 . Thus, the application of a high biomass load that gives rise to greater possibilities for the industrial pretreatment process should be taken into consideration 27 .…”

Elucidating the Ionic Liquid-Induced Mixed Inhibition of GH1 β-Glucosidase H0HC94

“…13,14 Recent studies have reported the use of [C 2 C 1 im][MeCO 2 ] for improving enzymatic saccharification and ethanol production from rice straw. 15 Additionally, the potential of the perennial grass Pennisetum polystachion as a biofuel source has been investigated with aqueous [C 2 C 1 im][MeCO 2 ] pretreatment. 16 Extraction of lipid from Chlorella vulgaris using high hydrostatic pressure treatment with [C 2 C 1 im][MeCO 2 ] has also been explored.…”