Cholinium amino acids ionic liquids ([Ch][AA] ILs), a novel type of bio-ILs that can easily be prepared from renewable biomaterials, were investigated for pretreatment of rice straw by selective extraction of lignin from this abundant lignocellulosic biomass material. Of the eight ILs examined, most were demonstrated to be excellent pretreatment solvents. Upon pretreatment using these ILs, the initial saccharification rates of rice straw residues were substantially improved as well as the extent to which polysaccharides could be digested (>90% for cellulose and >60% for xylan). Enzymatic hydrolysis of pretreated rice straw by Trichoderma reesei cellulase/xylanase furnished glucose and xylose with the yields in excess of 80% and 30%, respectively. Detailed spectroscopic characterization showed that the enhancement of polysaccharides degestibility derived mainly from delignification rather than changes in cellulose crystallinity. The yields of fermentable reducing sugars were significantly improved after individual optimization of pretreatment temperature and duration. With [Ch][Lys] as the solvent, the sugar yields of 84.0% for glucose and 42.1% for xylose were achieved after pretreatment at 90°C for 5 h. The IL [Ch][Lys] showed excellent reusability across five successive batches in pretreatment of rice straw. These bio-ILs performed as well as or better than previously investigated non-renewable ILs, and thus present a new and environmentally friendly way to pretreat lignocellulose for production of fermentable sugars and total utilization of the biomass.

Deep eutectic solvents (DESs) are eutectic mixtures of salts and hydrogen bond donors with melting points low enough to be used as solvents. DESs have proved to be a good alternative to traditional organic solvents and ionic liquids (ILs) in many biocatalytic processes. Apart from the benign characteristics similar to those of ILs (e.g., low volatility, low inflammability and low melting point), DESs have their unique merits of easy preparation and low cost owing to their renewable and available raw materials. To better apply such solvents in green and sustainable chemistry, this review firstly describes some basic properties, mainly the toxicity and biodegradability of DESs. Secondly, it presents several valuable applications of DES as solvent/co-solvent in biocatalytic reactions, such as lipase-catalyzed transesterification and ester hydrolysis reactions. The roles, serving as extractive reagent for an enzymatic product and pretreatment solvent of enzymatic biomass hydrolysis, are also discussed. Further understanding how DESs affect biocatalytic reaction will facilitate the design of novel solvents and contribute to the discovery of new reactions in these solvents.

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HMF has been efficiently upgraded into HMFCA with a good yield by using a highly HMF-tolerant strain Comamonas testosteroni SC1588.

In this work, 28 cholinium ionic liquids (ILs), most of which are good solvents for dissolving lignin, were used for rice straw pretreatment to improve subsequent enzymatic hydrolysis. The anion exerted a significant effect on the pretreatment effectiveness of the IL as well as the subsequent enzymatic hydrolysis efficiency of rice straw residues. The presence of the basic group(s) in the anion significantly enhanced the IL pretreatment effectiveness, while the carboxyl, hydroxyl and aromatic groups had a negative impact on IL delignification. Except for amino acid-based ILs, the delignification abilities of the ILs are linearly and positively correlated with the pKa values of the conjugate acids of the anions. Of the ILs tested, amino acid-based ILs, especially basic amino acid-based ILs, are the most effective pretreatment solvents. Satisfactory reducing sugar yields (81% for glucose and 26% for xylose) were obtained in the enzymatic hydrolysis of rice straw pretreated by cholinium argininate ([Ch][Arg]) under a pretty mild pretreatment severity (60°C, 6 h). The results presented in this work may be useful for rational design of novel and green ILs for delignification of lignocellulose.

Antimicrobial peptide (AMP) can be a promising alternative in various domains. However, further risk information is required. In this study, mice were orally administrated different dosages of recombinant AMP microcin J25 (4.55, 9.1, and 18.2 mg/kg; MccJ25) for 1 week, and the toxicity risk impacts were examined. We evidenced that middle-dosage administration mice had a lower inflammation, better body weight, and ameliorated mucosal morphology, accompanied by reduced intestinal permeability and tighter intestinal barrier. Fecal microbiota composition analysis in middle-or low-dosage mice revealed the Bifidobacterium count was increased and the coliform bacteria count was decreased, and increased in shortchain fatty acid levels. Unexpectedly, there was a risk that high-dosage mice increased intestinal permeability and imbalance of intestinal bacteria. Taken together, these data indicated a safe threshold for usage of MccJ25 in clinical practice. Such studies can effectively enhance the safety of various aspects such as food preservative and drug.

What is the most significant result of this study? The most importanto bservation of this study is the biocata-lyst-Meyerozyma guilliermondii SC1103-since the cells of this yeast are much more tolerant to 5-hydroxymethylfurfural (HMF) compared to microbesr eported previously.I na ddition, the efficiency of the biocatalytic HMF reduction as well as its selectivity are very high. What new scientific questions/problems doest his work raise? We think that one of the new scientific questionsm ay be the mechanism by which this yeast strain can tolerate high levels of HMF.U nderstandingt his mechanism will provideu seful in-formationf or the rational modificationo ft he strains for various applications involving HMF. What is the story behindt he cover? The yeast train plays ad ominant role in the biocatalytic reduction of HMF,w hich earned the title of the conductor.G lucose, fructose(the precursors for the synthesis of HMF), HMF,a nd 2,5-bis(hydroxymethyl)furan act as the piano players. So we named this cover image "TheConductor and Its Players". Invited for this month'sc over is the group of Min-Hua Zong at South ChinaU niversity of Technology.T he image shows the selectives ynthesis of 2,5-bis(hydroxymethyl)furan from 5-hydroxymethylfurfural (HMF) using highly HMF-tolerantw hole cells.