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Current study is the first report of the combined application of chemical (deep eutectic solvent), physical (microwave irradiation) and biological (laccase) pretreatment strategies for enhancing the enzymatic digestibility of rice straw biomass. Pretreated rice straw biomass was saccharified by cellulase/xylanase from Aspergillus japonicus DSB2 to get a sugar yield of 252.36 mg/g biomass. Design of Experiment based optimization of pretreatment and saccharification variables increased the total sugar yield by 1.67 times (421.5 mg/g biomass, saccharification efficiency 72.6%). Sugary hydrolysate was ethanol-fermented by Saccharomyces cerevisiae and Pichia stipitis to achieve an ethanol yield of 214 mg/g biomass (bioconversion efficiency 72.5%). Structural/chemical aberrations induced in the biomass due to pretreatment were elucidated by X-ray diffraction, scanning electron microscopy, Fourier-transform infrared spectroscopy, and 1 H nuclear magnetic resonance techniques to unravel the pretreatment mechanisms. Combined application of various physico-chemical/biological pretreatment may be a promising approach for proficient bioconversion of rice straw biomass., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Quest for renewable/eco-friendly energy sources has received immense focus in recent years. Current study involved consolidated bioprocessing of Saccharum spontaneum biomass (SSB) for biofuel-ethanol generation in a 'one pot consolidated bioprocess' (OPCB). SSB was pretreated with protic ionic liquid, triethylamine-bisulfate ([TEA][HSO 4 ]), saccharified in-situ with cellulase/xylanase enzymes, and the released sugars were fermented to ethanol. Pretreatment and saccharification processes were optimized under OPCB to achieve 2.70-fold increased sugar yield i.e. from 196.56 to 531.00 mg/g biomass. Fermentation of sugars yielded ethanol at 209.6 mg/g biomass at a bioconversion efficiency of 72.56 %. The pretreated SSB was comprehensively examined by/for XRD, NMR, SEM, FT-IR, and properties such as water retention capacity, surface area and cellulase adsorption ability to elucidate functional mechanisms of [TEA][HSO 4 ] pretreatment., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

This work aimed to study the hydrolysis of ionic liquid (IL) pretreated sugarcane tops (SCT) biomass with in-house developed IL-stable enzyme preparation, from a fungal isolate Aspergillus flavus PN3. Maximum reducing sugar yield (181.18 mg/g biomass) was obtained from tris (2-hydroxyethyl) methylammonium-methylsulfate ([TMA]MeSO 4 ) pretreated biomass. Pretreatment parameters were optimized to attain enhanced sugar yield (1.57-fold). Functional mechanism of IL mediated pretreatment of SCT biomass was elucidated by SEM, XRD, FTIR and 1 H NMR studies. Furthermore, nanobiocatalysts prepared by immobilization of enzyme preparation by covalent coupling on magnetic nanoparticles functionalized with amino-propyl triethoxysilane, were assessed for their hydrolytic efficacy and reusability. Nanobiocatalysts were examined by SEM and FTIR analysis for substantiation of immobilization. This is the first ever report of application of magnetic nanobiocatalysts for saccharification of IL-pretreated sugarcane tops biomass., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

A novel strategy involving sodium dodecylsulfate (SDS) (SDS assisted tris (2-hydroxyethyl) methyl- ammonium methyl sulphate ([TMA][MeSO 4 ], ionic liquid) pretreatment of Saccharum spontaneum biomass (SSB) following its enzymatic saccharification, and conversion into ethanol-biofuel in a consolidated bioprocess (CBP) was developed. Ionic liquid stable enzyme preparation developed from Bacillus subtilis G 2 was used for saccharification. Optimized pretreatment and saccharification variables enhanced the sugar yield (2.35-fold), which was fermented to ethanol content of 104.42 mg/g biomass with an efficiency of 35.73%. The pretreated biomass was examined for textural/ultrastructural alterations by scanning electron microscopy (SEM), 1 H/ 13 C nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), surface area measurements, water retention value, and cellulase adsorption isotherms. The combined [TMA][MeSO 4 ] and SDS pretreatment disrupted the lignocellulosic microfibrils, and increased the porosity and surface area. The study provides new mechanistic insights on combined IL and surfactant pretreatment of biomass for its efficient conversion to biofuel., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

The current study presents the first ever report of surfactant (Tween-20) assisted ionic liquid IL, (1-ethyl-3-methylimidazolium methane sulphonate [Emim][MeSO 3 ]) pretreatment of Parthenium hysterophorus biomass, its saccharification by in-house developed enzyme cocktail from Aspergillus aculeatus PN14, and fermentation of sugars to bioethanol under consolidated bioprocess. Optimization of pretreatment process variables viz. biomass loading, temperature and time, resulted in enhanced sugar yield (40.1%) upon saccharification of pretreated biomass with IL-stable cellulase and xylanase enzymes from an IL-tolerant newly isolated fungus Aspergillus aculeatus PN14. Physicochemical analysis of surfactant assisted IL-pretreated biomass by SEM, FT-IR and XRD provided molecular insights into inter/intra molecular ultrastructural changes in the biomass that eased the saccharification. Thorough understanding of chemical/molecular structure of biomass may help developing customized pretreatment regimes of apt severity which might result in enhanced accessibility of enzymes to biomass, and hence more sugar content., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Ionic liquid (IL) pretreatment represents an effective strategy for effective fractionation of lignocellulosic biomass (LB) to fermentable sugars in a biorefinery. Optimization of combinatorial pretreatment of sugarcane bagasse (SCB) with IL (1-butyl-3-methylimidazolium chloride [Bmim]Cl) and surfactant (PEG-8000) resulted in enhanced sugar yield (16.5%) upon enzymatic saccharification. The saccharification enzymes (cellulase and xylanase) used in the current study were in-house produced from a novel IL-tolerant fungal strain Aspergillus assiutensis VS34, isolated from chemically polluted soil, which produced adequately IL-stable enzymes. This is the first ever report of IL-stable cellulase/xylanase enzyme from Aspergillus assiutensis. To get the mechanistic insights of combinatorial pretreatment physicochemical analysis of variously pretreated biomass was executed using SEM, FT-IR, XRD, and 1 H NMR studies. The combined action of IL, surfactant and ultrasound had very severe and distinct effects on the ultrastructure of biomass that subsequently resulted in enhanced accessibility of saccharification enzymes to biomass, and increased sugar yield., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Biorefining of lignocellulosic biomass to fuels/chemicals has recently gained immense research momentum. Current study reports sequential pretreatment of sunflower stalk (SFS) biomass in a combinatorial regime involving alkali (NaOH) and ionic liquid 1-butyl-3-methyl imidazolium chloride. The pretreatment enhanced the enzymatic digestibility, and resulted in increased sugar yield (163.42 mg/g biomass) as compared to standalone pretreatment using alkali (97.38 mg/g biomass) or ionic liquid (79.6 mg/g biomass). Ultrastructural and morphological analysis (FTIR and SEM) of pretreated biomass showed that the combined ionic liquid and alkali pretreatment causes more drastic alterations in the biomass ultrastructure as compared to alone ionic liquid or alkali pretreatment. Thus, combined pretreatment led to ease of enzymatic saccharification and consequent increased sugar yield, and this observation was corroborated by physicochemical analysis of the pretreated biomass. The pretreated SFS biomass was subjected to consolidated bioprocessing for its direct conversion to bioethanol in a single vessel., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Bioprospecting of novel probiotic strains especially from unexplored eco-niches has been a continuous practice. Enterococcus faecium K1, an isolate from indigenously fermented milk product kalarei possesses numerous desirable functional attributes. In current study, E. faecium K1 has been used for EPS production, and it yielded 355 ± 0.019 mg/L EPS. EPS demonstrates remarkable hypocholesterolemic, antioxidant, antibiofilm, and emulsification characteristics. EPS is constituted of mannose, glucose and galactose. SEM analysis reveals flake like compact structure of EPS while TEM and X-ray diffractogram confirms the amorphous structure of EPS. FTIR substantiates the functional groups/bonds typical of polysaccharides. Thermal analysis indicates adequate stability of EPS at 237 °C with average weight loss of 22%. E. faecium K1 EPS possesses unique functional bioactivities and physicochemical characteristics, and may potentially be explored for applications in food/pharmaceutical industries., (Copyright © 2018 Elsevier Ltd. All rights reserved.)