Fermentable Sugar Production from a Coffee Processing By-product after Deep Eutectic Solvent Pretreatment

Deep eutectic solvents: Preparation, properties, and food applications

Deep Eutectic Solvents (DESs) emerge as innovative 21st-century solvents, supplanting traditional ones like ethanol and n-hexane. Renowned for their non-toxic, biodegradable, and water-miscible nature with reduced volatility, DESs are mostly synthesized through heating and stirring method. Physicochemical properties such as polarity, viscosity, density and surface tension of DESs influenced their application. This review paper gives the overview of application of eco-benign DESs in fruits, vegetables, cereals, pulses, spices, herbs, plantation crops, oil seed crops, medicinal and aromatic plants, seaweed, and milk for the extraction of bioactive compounds. Also, it gives insight of determination of pesticides, insecticides, hazardous and toxic compounds, removal of heavy metals, detection of illegal milk additive, purification of antibiotics and preparation of packaging film. Methodologies for separating bioactive compounds from DESs extracts are systematically examined. Further, safety regulations of DESs are briefly discussed and reviewed literature reveals prevalent utilization of DES-based bioactive compound rich extracts in cosmetics, indicating untapped potential of their application in the food industry.

Development of Sustainable Biorefinery Processes Applying Deep Eutectic Solvents to Agrofood Wastes

The growing demand for renewable energies and the application of sustainable and economically viable biorefinery processes have increased the study and application of lignocellulosic biomass. However, due to lignocellulosic biomass recalcitrance hindering its efficient utilization, the pretreatment in the biorefinery is an essential stage for success in the process. Therefore, Deep Eutectic Solvent (DES) has emerged as a promising green pretreatment. During this study, the effect of choline chloride [ChCl]:glycerol and [ChCl]:urea on sugarcane bagasse and brewery bagasse is evaluated. Results have demonstrated that using [ChCl]:glycerol in SCB reduced about 80% and 15% for acid-soluble lignin and Klason lignin, respectively, and improved efficiency on saccharification yields, achieving conversions of 60, 80, and 100% for glucan, xylan, and arabinan, correspondingly. In the case of BSG saccharification yields, about 65% and 98% are attained for glucan and xylan, respectively, when [ChCl]:glycerol was employed. These results confirm the effectiveness and facility of DES pretreatment as a suitable method that can improve the biorefinery processes.

Defatted rice bran pretreated with deep eutectic solvents and sequential use as feedstock for subcritical water hydrolysis

Deffated rice bran has potential to processing into ethanol due to its lignocellulosic composition and agricultural productivity. The composition of the pretreated deffated rice bran with Deep Eutectic Solvent was investigated aiming the production of sugars and bioproducts using subcritical water hydrolysis. Changes in the deffated rice bran composition at different pretreatment times and mixtures of deep eutectic solvent were evaluated by the derivative of thermogravimetric analysis. The pretreated deffated rice bran presented an enrichment in the content of hemicelluloses (281.0%) and delignification (59.3 %). Under the same condition of subcritical water hydrolysis (230 °C/R-100) the yield of fermentable sugars increased 2.20 times in the same study time interval (20 min) when comparing pretreated and untreated deffated rice bran.

Fermentative Lactic Acid Production From Lignocellulosic Feedstocks: From Source to Purified Product

The second (lignocellulosic biomass and industrial wastes) and third (algal biomass) generation feedstocks gained substantial interest as a source of various value-added chemicals, produced by fermentation. Lactic acid is a valuable platform chemical with both traditional and newer applications in many industries. The successful fractionation, separation, and hydrolysis of lignocellulosic biomass result in sugars’ rich raw material for lactic acid fermentation. This review paper aims to summarize the investigations and progress in the last 5 years in lactic acid production from inexpensive and renewable resources. Different aspects are discussed—the type of raw materials, pretreatment and detoxification methods, lactic acid-producers (bacteria, fungi, and yeasts), use of genetically manipulated microorganisms, separation techniques, different approaches of process organization, as well as main challenges, and possible solutions for process optimization.

Some applications of deep eutectic solvents in alkylation of heterocyclic compounds: A review of the past 10 years

This mini-review encapsulates the latest findings (past 10 years) in the field of the deep eutectic solvents (DESs) application in the alkylation/arylation of different heterocyclic compounds. These solvents have been developed to fulfill the green chemistry concept demands and have been proven excellent for the application in various fields. This review describes their application in different types of alkylation, C-, N-, O- and S-alkylation. P-alkylation has not yet been published within this scope. Not only have the authors in this study proven that DESs could be successfully applied for this specific type of reaction, but they have also offered an excellent insight into the mechanisms of their action.

Ternary deep eutectic solvents for effective biomass deconstruction at high solids and low enzyme loadings

Ternary deep eutectic solvents (DESs) were developed to enable rapid and high-solid biomass pretreatment as well as concentrated sugar hydrolysate production. Six ternary DESs constituted choline chloride (ChCl) or guanidine hydrochloride (GH) as a hydrogen bond acceptor (HBA), ethylene glycol (EG) or propylene glycol (PG) or glycerin (GLY) as a polyol-based hydrogen bond donor (HBD), and p-toluenesulfonic acid (PTSA) as an acidic HBD. GH-EG-PTSA was the most effective, evidenced by 79% xylan and 82% lignin removal in only 6 min at 120 °C and 10 wt% solid loading. Even at 35 wt% solid loading, both GH-EG-PTSA and ChCl-EG-PTSA still removed more than 60% xylan and lignin in 30 min. Using a 20% solid loading and a low enzyme loading of 5 mg protein/g solid, 128 g/L glucose and 20 g/L xylose was obtained, with a glucose yield of 78.4%. Overall, this study demonstrated novel and high-performance ternary DESs for effective lignocellulose deconstruction.