Complex effect of lignocellulosic biomass pretreatment with 1-butyl-3-methylimidazolium chloride ionic liquid on various aspects of ethanol and fumaric acid production by immobilized cells within SSF

Transformation of Enzymatic Hydrolysates of Chlorella–Fungus Mixed Biomass into Poly(hydroxyalkanoates)

The production of poly(hydroxylalkanoates) (PHA) is limited by the high cost of the feedstock since various biomass wastes look attractive as possible sources for polymer production. The originality of this present study is in the biotransformation of mixed Chlorella-based substrates into PHAs. The synthetic potential of Cupriavidus necator B8619 cells was studied during the bioconversion of algae biomass in mixtures with spent immobilized mycelium of different fungi (genus Rhizopus and Aspergillus) into PHAs. The biomass of both microalgae Chlorella and fungus cells was accumulated due to the use of the microorganisms in the processes of food wastewater treatment. The biosorption of Chlorella cells by fungal mycelium was carried out to obtain mixed biomass samples (the best ratio of “microalgae:fungi” was 2:1) to convert them by C. necator B8619 into the PHA. The influence of conditions used for the pretreatment of microalgae and mixed types of biomass on their conversion to PHA was estimated. It was found that the maximum yield of reducing sugars (39.4 ± 1.8 g/L) can be obtained from the mechanical destruction of cells by using further enzymatic hydrolysis. The effective use of the enzymatic complex was revealed for the hydrolytic disintegration of treated biomass. The rate of the conversion of mixed substrates into the biopolymer (440 ± 13 mg/L/h) appeared significantly higher compared to similar known examples of complex substrates used for C. necator cells.

Sulfur containing mixed wastes in anaerobic processing by new immobilized synthetic consortia

Methanogenic biotransformation of unusual substrates (sulfur (S)-containing wastes: non-purified vacuum gas oil, straight-run gasoline fraction (Naphtha), gas condensate, and straight-run diesel fraction) coming from oil industry after their oxidative desulfurization was investigated. Nitrogen-containing wastes (hydrolysates of chicken manure and Chlorella vulgaris biomass) were added as co-substrates to mixture with oil industry wastes. The 100 % conversion of S-organic compounds to inorganic sulfide accumulated in the reaction liquid medium was achieved with simultaneous production of biogas containing high methane percent (greater than 70 %). Polishing of effluents from methane tank was carried out by denitrifying oxidation of ammonium (DEAMOX). The high process efficiency was due to use of original immobilized artificial consortia at the stage of methanogenesis and DEAMOX. This study reveals the real potential in the processing of very complex mixtures of large-scale wastes, usually inhibiting methanogenesis, by developing biocatalysts based on synthetic biology approaches.

The application of green solvent in a biorefinery using lignocellulosic biomass as a feedstock

The high dependence on crude oil for energy utilization leads to a necessity of finding alternative sustainable resources. Solvents are often employed in valorizing the biomass into bioproducts and other value-added chemicals during treatment stages. Unfortunately, despite the effectiveness of conventional solvents, hindrances such as expensive solvents, unfavourable environmental ramifications, and complicated downstream separation systems often occur. Therefore, the scientific community has been actively investigating more cost-effective, environmentally friendly alternatives and possess the excellent dissolving capability for biomass processing. Generally, 'green' solvents are attractive due to their low toxicity, economic value, and biodegradability. Nonetheless, green solvents are not without disadvantages due to their complicated product recovery, recyclability, and high operational cost. This review summarizes and evaluates the recent contributions, including potential advantages, challenges, and drawbacks of green solvents, namely ionic liquids, deep eutectic solvents, water, biomass-derived solvents and carbon dioxide in transforming the lignocellulosic biomass into high-value products. Moreover, research opportunities for future developments and potential upscale implementation of green solvents are also critically discussed.

Using an SGB Decision Tree Approach to Estimate the Properties of CRM Made by Biomass Pretreated with Ionic Liquids

The use of ionic liquids (ILs) for biomass pretreatment to produce cellulose-rich materials (CRMs) has been well proven. In this research, due to the wide range of applications and ease of using artificial intelligence procedures, on the basis of the algorithm of stochastic gradient boosting (SGB) decision tree, an artificial intelligence approach is proposed to estimate the properties of cellulose-rich materials (CRMs). That being the case, the dataset of the empirical output values was gathered and was randomly broken down into datasets for testing and training. These results show that the best forecasting tool for calculating the properties of CRMs is the developed model. Furthermore, the accuracy of the databank of the biodiesel target values has been examined. In contrast, the influences of model contributed variables on the output have been examined as a new issue. It reveals that the most influencing variable in determining the properties of CRMs is the cellulose enrichment factor. Therefore, this research provides an innovative and accurate tool for predicting the properties of CRMs and sensitivity investigation on effective parameters to help investigators developing the optimized process.

Machine learning prediction of cellulose-rich materials from biomass pretreatment with ionic liquid solvents

Ionic liquid solvents (ILSs) have been effectively utilized in biomass pretreatment to produce cellulose-rich materials (CRMs). Predicting CRM properties and evaluating multi-dimensional relationships in this system are necessary but complicated. In this work, machine learning algorithms were applied to predict CRM properties in terms of cellulose enrichment factor (CEF) and solid recovery (SR), using 23-feature datasets from biomass characteristics, operating conditions, ILSs identities, and catalyst. Random forest algorithm was found to have the highest prediction accuracy with RMSE and R² of 0.22 and 0.94 for CEF, as well as 0.07 and 0.84 for SR, respectively. Highly influential features on making predictions were mainly from biomass characteristics andILS treatment'soperating conditions, totally contributed 80% on CEF and 60% on SR. One- and two-way partial dependence plots were used to explain/interpret the multi-dimensional relationships of the most important features. Our findings could be applied in designing new ILSs and optimizing the process conditions.

Resource recovery and biorefinery potential of apple orchard waste in the circular bioeconomy

In this review investigate the apple orchard waste (AOW) is potential organic resources to produce multi-product and there sustainable interventions with biorefineries approaches to assesses the apple farm industrial bioeconomy. The thermochemical and biological processes like anaerobic digestion, composting and , etc., that generate distinctive products like bio-chemicals, biofuels, biofertilizers, animal feed and biomaterial, etc can be employed for AOW valorization. Integrating these processes can enhanced the yield and resource recovery sustainably. Thus, employing biorefinery approaches with allied different methods can link to the progression of circular bioeconomy. This review article mainly focused on the different biological processes and thermochemical that can be occupied for the production of waste to-energy and multi-bio-product in a series of reaction based on sustainability. Therefore, the biorefinery for AOW move towards identification of the serious of the reaction with each individual thermochemical and biological processes for the conversion of one-dimensional providences to circular bioeconomy.

Transforming lignocellulosic biomass into biofuels enabled by ionic liquid pretreatment

Processes that can convert lignocellulosic biomass into biofuels and chemicals are particularly attractive considering renewability and minimal environmental impact. Ionic liquids (ILs) have been used as novel solvents in the process development in that they can effectively deconstruct recalcitrant lignocellulosic biomass for high sugar yield and lignin recovery. From cellulose-dissolving ILs to choline-based and protic acidic ILs, extensive research in this field has been done, driven by the promising future of IL pretreatment. Meanwhile, shortcomings and technological hurdles are ascertained during research and developments. It is necessary to present a general overview of recent developments and challenges in this field. In this review paper, three aspects of advances in IL pretreatment are critically analyzed: biocompatible ILs, protic acidic ILs and combinatory pretreatments.

Formation and use of anaerobic consortia for the biotransformation of sulfur-containing extracts from pre-oxidized crude oil and oil fractions

A new solution for fossil raw materials desulfurization based on a hybrid chemical-biocatalytic scheme with biogas and sulfide production is proposed.·H₂O₂, formic acid and Na₂MoO₄ were used for petroleum or oil fractions pre-oxidation. Ethanol or dimethylformamide was used as extractant to remove sulfur-contained compounds from pre-oxidized straight-run diesel oil fraction, non-hydro treated vacuum gas oil, gas condensate or crude oil. Compositions of cells (anaerobic sludge, Desulfovibrio vulgaris, Clostridium acetobutilycum, Rhodococcus ruber, Rhodococcus erythropolis) were specially developed, immobilized in poly(vinyl alcohol) cryogel and used for methanogenic treatment of sulfur-containing extracts, diluted with phosphate buffer (pH 7.2) and hydrolysates of renewable raw materials. The sulfur coming into the reactor with the extracts was 100% converted to inorganic sulfide or cell biomass. The ratio of methane in the biogas was 68-76%. Bioluminescent express-methods were used to control the possible toxicity of media and metabolic activity of cells used as biocatalysts.

A Review on the Partial and Complete Dissolution and Fractionation of Wood and Lignocelluloses Using Imidazolium Ionic Liquids

Ionic liquids have shown great potential in the last two decades as solvents, catalysts, reaction media, additives, lubricants, and in many applications such as electrochemical systems, hydrometallurgy, chromatography, CO2 capture, etc. As solvents, the unlimited combinations of cations and anions have given ionic liquids a remarkably wide range of solvation power covering a variety of organic and inorganic materials. Ionic liquids are also considered "green" solvents due to their negligible vapor pressure, which means no emission of volatile organic compounds. Due to these interesting properties, ionic liquids have been explored as promising solvents for the dissolution and fractionation of wood and cellulose for biofuel production, pulping, extraction of nanocellulose, and for processing all-wood and all-cellulose composites. This review describes, at first, the potential of ionic liquids and the impact of the cation/anion combination on their physiochemical properties and on their solvation power and selectivity to wood polymers. It also elaborates on how the dissolution conditions influence these parameters. It then discusses the different approaches, which are followed for the homogeneous and heterogeneous dissolution and fractionation of wood and cellulose using ionic liquids and categorize them based on the target application. It finally highlights the challenges of using ionic liquids for wood and cellulose dissolution and processing, including side reactions, viscosity, recyclability, and price.

Protein surface engineering of endoglucanase Penicillium verruculosum for improvement in thermostability and stability in the presence of 1-butyl-3-methylimidazolium chloride ionic liquid

Thermostability and stability in ionic liquids are essential properties of cellulases that are applied in industrial processes of bioconversion. Engineering of protein surface of endoglucanase II from Penicillium verruculosum was used to improve the enzyme thermostability and stability in 1-butyl-3-methylimidazolium chloride ([Bmim]Cl). The engineering was based on analysis of the protein surface topography and enhanced by multiple sequence alignment and ΔΔG calculations. In the case of the thermostability, half-life time was improved in 1.3-1.6 times at 70 °C and 1.2-1.4 times at 80 °C. In the case of the stability in [Bmim]Cl, the residual activity after 72 h of incubation in the presence of [Bmim]Cl (50 g/L, 50 °C, pH 4.5) was 1.7-1.9 times greater for the tailored enzyme. The yield of reducing sugars after enzymatic hydrolysis of aspen wood pretreated with [Bmim]Cl was 10-20% higher with the tailored endoglucanase.

Consolidated bioprocessing of surfactant-assisted ionic liquid-pretreated Parthenium hysterophorus L. biomass for bioethanol production

The current study presents the first ever report of surfactant (Tween-20) assisted ionic liquid IL, (1-ethyl-3-methylimidazolium methane sulphonate [Emim][MeSO₃]) 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.

Critical applications of Mucor circinelloides within a biorefinery context

The establishment of an efficient and feasible biorefinery model depends on, among other factors, particularly the selection of the most appropriate microorganism. Mucor circinelloides is a dimorphic fungus species able to produce a wide variety of hydrolytic enzymes, lipids prone to biodiesel production, carotenoids, ethanol, and biomass with significant nutritional value. M. circinelloides also has been selected as a model species for genetic modification by being the first filamentous oleaginous species to have its genome fully characterized, as well as being a species characterized as a potential bioremediation agent. Considering the potential of replacing several nonrenewable feedstocks is widely dependent on fossil fuels, the exploitation of microbial processes and products is a desirable solution for promoting a green and sustainable future. Here, we introduce and thoroughly describe the recent and critical applications of this remarkable fungus within the context of developing a fungal-based biorefinery.

Production of various organic acids from different renewable sources by immobilized cells in the regimes of separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SFF)

The study was aimed at production of different organic acids (OA) (lactic, fumaric, or succinic) by various microbial cells (filamentous fungi Rhizopus oryzae (F-814, F-1127) and bacteria Actinobacillus succinogenes B-10111) immobilized into poly(vinyl alcohol) (PVA) cryogel from diverse renewable raw materials (wheat and rice straw, aspen and pine sawdust, Jerusalem artichoke stems and tubers, biomass of macro- and microalgae) under batch conditions. The process productivity, bulk output and OA concentrations were higher in case of using immobilized cells than in case of free cells under identical conditions. A higher OA productivity was reached via simultaneous enzymatic saccharification and microbial fermentation (SSF) of same raw materials as compared to their separate enzymatic hydrolysis and fermentation of accumulated reducing sugars (SHF). Maximal concentrations of all OAs studied were obtained for bioconversion of Jerusalem artichoke tubers. The immobilized cells were used in long-term conversion of various renewable materials to OAs in SSF.

Application of ionic liquid and alkali pretreatment for enhancing saccharification of sunflower stalk biomass for potential biofuel-ethanol production

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.