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In this study, liquid-phase microplasma technology (LPMPT) was employed to facilitate the liquefaction of bamboo shoot shell (BSS) in polyethylene glycol 400 (PEG 400) and ethylene glycol (EG) mixture. Effects of liquefaction conditions such as liquefaction time, catalyst percentage, solvent/BSS mass ratio, PEG/EG volume ratio on liquefaction were investigated experimentally. The results showed that the introduction of LPMPT significantly shortened the liquefaction time to 3 min without extra heating. The liquefaction yield reached 96.73% under the optimal conditions. The formation of massive reactive species and instantaneous heat accumulation both contributed to the rapid liquefaction of BSS. Thus, LPMPT could be considered as a simple and efficient method for the assistance of biomass fast liquefaction. [ABSTRACT FROM AUTHOR]

• New effective approach for lignin depolymerisation into renewable chemicals. • Energy-efficient, scalable biomass conversion enabled by low-temperature plasmas. • Fenton reaction assisted high conversion yield under industry relevant conditions. • Chemical industry-sought product rich in aromatics and dicarboxylic acids. Lignin valorisation into renewable fuels and platform chemicals is desirable but still encounters major challenges due to lignin's recalcitrant structure, and the lack of cost-, energy-, and material efficient conversion processes. Herein, we report a low-temperature plasma-based route to lignin depolymerisation at mild conditions. The discharge over ethanol surface locally creating a high-energy and reactive environment rich in free electrons, energetic H radicals, and other reactive species, is well suited for lignin depolymerisation. Furthermore, assisted with a Fenton reaction (by adding Fe 2 O 3 and H 2 O 2) to sustain a more oxidative environment, the lignin conversion yield increases from 42.6% to 66.0%. Thus-obtained renewable chemicals are rich in aromatics and dicarboxylic acid derivatives. The proposed strategy on intensifying reactive chemistry by high-power plasmas enables an effective power-to-chemicals conversion of lignin and may provide useful guidelines for modern biorefineries. [ABSTRACT FROM AUTHOR]

Graphical abstract The PEL process ((a) sawdust and cellulose, (b) corn cob and holocellulose, (c) corn stalk and lignin, (d) rice straw, (e) brief schematic diagram of PEL experimental apparatus, (f) gas product, (g) liquid product, (h) solid residue). Highlights • Discharge characteristics and catalytic efficiency of four catalysts were compared. • The liquefaction yield of sawdust reached 97.20% in 2 min. • A high liquefaction yield was obtained in the presence of a salt catalyst. • Cellulose, holocellulose, and lignin were extracted and liquefied successfully. • Plasma electrolytic technology could successfully liquefy lignocellulosic biomass. Abstract In this research, we compared the discharge characteristics and catalytic efficiency of sulfuric acid, p-toluenesulfonic acid, and their respective sodium salts (sodium sulfate and sodium p-toluenesulfonate) in sawdust liquefaction and found that sulfuric acid was the optimal catalyst when glycerol was used as solvent during the plasma electrolytic liquefaction (PEL) process. When sodium p-toluenesulfonate was used as the only catalyst, the liquefaction yield reached 83.51% after 25 min. This yield was higher than that obtained using sodium sulfate as the catalyst (60.63%) because different concentrations of H ions were produced in PEL. Cellulose, lignin, and holocellulose were extracted from sawdust and successfully liquefied in PEL, illustrating the universality of PEL. The optical emission spectra of the different biomass during the PEL process were similar, indicating that the kinds of free radicals produced were similar, which can accelerate the liquefaction of sawdust. [ABSTRACT FROM AUTHOR]

In this work, plasma electrolytic technology was successfully employed to achieve fast liquefaction of sawdust when polyethylene glycol 200 (PEG 200) and glycerol were used as liquefacient in the presence of the catalyst sulfuric acid. Results showed that H ions could heat the solution effectively during the plasma electrolytic liquefaction (PEL) process. The influence of some key parameters including liquefaction time, catalyst percentage, liquefacient/sawdust mass ratio, and PEG 200/glycerol molar ratio on the liquefaction yield were investigated. Based on the results of single factor experiments, response surface methodology (RSM) was applied to optimize the liquefaction process. Under the optimal conditions that is liquefaction time of 5.10 min, catalyst percentage of 1.05%, liquefacient/sawdust mass ratio of 7.12/1 and PEG 200/glycerol molar ratio of 1.40/1, the liquefaction yield reached 99.48%. Hence, it could be concluded that PEL has good application potential for biomass fast liquefaction. [ABSTRACT FROM AUTHOR]

[Display omitted] • New approach to improve the yields of astaxanthin in Phaffia rhodozyma. • Plasma-activated water (PAW) generates oxidative stress in Phaffia rhodozyma. • Mechanisms of higher astaxanthin production revealed by proteomics analysis. • Prospective biotechnology based on PAW for sustainable astaxanthin production. Astaxanthin is used extensively in the nutraceutical, aquaculture, and cosmetic industries. The current market necessitates higher astaxanthin production from Phaffia rhodozyma (P. rhodozyma) due to its higher cost compared to chemical synthesis. In this study, a bubble discharge reactor was developed to generate plasma-activated water (PAW) to produce PAW-made yeast malt (YM) medium. Due to oxidative stress induced by PAW, strains cultured in 15 and 30 min-treated PAW-made medium produced 7.9 ± 1.2 % and 12.6 ± 1.4 % more carotenoids with 15.5 ± 3.3 % and 22.1 ± 1.3 % more astaxanthin, respectively. Reactive oxygen species (ROS) assay results showed that ROS generated by plasma-water interactions elevated intracellular ROS levels. Proteomic analysis revealed increased expression of proteins involved in the cellular response to oxidative stress as well as carotenoid biosynthesis, both of which contribute to higher yields of astaxanthin. Overall, this study supports the potential of PAW to increase astaxanthin yields for industrial-scale production. [ABSTRACT FROM AUTHOR]