Evaluating the potential of different bioaugmented strains to enhance methane production during thermophilic anaerobic digestion of food waste.

Bioaugmentation technology for improving the performance of thermophilic anaerobic digestion (TAD) of food waste (FW) treatment is gaining more attention. In this study, four thermophilic strains (Ureibacillus suwonensis E11, Clostridium thermopalmarium HK1, Bacillus thermoamylovorans Y25 and Caldibacillus thermoamylovorans QK5) were inoculated in the TAD of FW system, and the biochemical methane potential (BMP) batch study was conducted to assess the potential of different bioaugmented strains to enhance methane production. The results showed that the cumulative methane production in groups inoculated with E11, HK1, Y25 and QK5 improved by 2.05%, 14.54%, 19.79% and 9.17%, respectively, compared with the control group with no inoculation. Moreover, microbial community composition analysis indicated that the relative abundance of the main hydrolytic bacteria and/or methanogenic archaea was increased after bioaugmentation, and the four strains successfully became representative bacterial biomarkers in each group. The four strains enhanced methane production by strengthening starch, sucrose, galactose, pyruvate and methane metabolism functions. Further, the correlation networks demonstrated that the representative bacterial genera had positive correlations with the differential metabolic functions in each bioaugmentation group. This study provides new insights into the TAD of FW with bioaugmented strains.

Unveiling the potential of novel recyclable deep eutectic solvent pretreatment: Effective separation of lignin from poplar hydrolyzed residue.

To effectively convert the fermentable sugars present in lignocellulosic biomass into biofuels and additional value-added products, it is crucial to remove lignin from the biomass. With the intention of expeditiously remove lignin from poplar wood and improve cellulose saccharification, an innovative ternary deep eutectic solvent (DES) benzyl triethyl ammonium chloride-ethylene glycol-FeCl3 (T-EG-F) was studied for the pretreatment of poplar hydrolyzed residue (PHR). The results revealed that following T-EG-F DES pretreatment at 130 °C for 4 h, the lignin removal rate reached 91.88 %. The effect of DES on PHR and regenerated lignin was comprehensively investigated using X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), Thermogravimetric (TG) and other characterization methods, providing valuable insights into the mechanism of this innovative biomass pretreatment. Moreover, there was a significant improvement in the enzyme digestibility of the DES pretreatment residue. At 48 h, the enzyme load of 30 FPU/g cellulose achieved a remarkable enzyme digestibility of 97.31 %, and this value exhibited a notable increase of 6.56 times compared to the untreated poplar sample. In addition, the T-EG-F could be recycled and reused. This study demonstrates that the potential of T-EG-F DES pretreatment as a green and efficient method for lignin dissociation from lignocellulosic biomass, offering a promising approach for biomass component separation.