MOESM1 of Penicillin acylase-catalyzed synthesis of N-bromoacetyl-7-aminocephalosporanic acid, the key intermediate for the production of cefathiamidine

Additional file 1. Additional figures including: Figure S1. Time courses of 7-ACA transformation catalyzed by various immobilized enzymes; Figure S2. Stability of 7-ACA in the absence and presence of PGA-750; Figure S3. The 7-ACA solubility in various buffer; Figure S4. Stability of 7-ACA at different pH; Figure S5. The stability of the immobilized enzyme PGA-750 at different pH

Enzymatic synthesis and anti-oxidative activities of plant oil-based ascorbyl esters in 2-methyltetrahydrofuran-containing mixtures

<p>Ascorbyl fatty acid esters are commercially interesting fat-soluble antioxidants. In this work, enzymatic synthesis of ascorbyl esters from less expensive and readily available plant oils, and their anti-oxidative activities are described. Among the immobilized lipases tested, <i>Candida antarctica</i> lipase B was the best for the synthesis of plant oil-based ascorbyl esters. The enzyme showed much better catalytic performances in the binary mixtures of biomass-based 2-methyltetrahydrofuran (MeTHF) and <i>t</i>-butanol than the previously preferred <i>t</i>-butanol. The conversions of 70–73% were obtained under the optimal reaction conditions after 24 h, with the unsaturated fatty acid esters (oleate and linoleate, 80–90%) as the major products. The immobilized lipase kept the relative activity of 80% after reuse for 6 batches in MeTHF-containing system. Besides, anti-oxidative activities of plant oil-based ascorbyl esters and ascorbic acid were comparable, which could remove α,α-diphenyl-β-picrylhydrazyl (DPPH) free radical of  >87%.</p

Facile and Simple Pretreatment of Sugar Cane Bagasse without Size Reduction Using Renewable Ionic Liquids–Water Mixtures

In this work, sugar cane bagasse pretreatment by renewable cholinium amino acids ionic liquids ([Ch]­[AA] ILs) and subsequent enzymatic hydrolysis of the residues were conducted. Six ILs tested were found to be effective for sugar cane bagasse pretreatment. Upon pretreatment using these ILs, the enzymatic digestion of this lignocellulosic biomass was improved significantly due to extensive delignification. The IL cholinium lysine ([Ch]­[Lys]) displayed excellent pretreatment efficiency with sugar cane bagasse of various sizes as the substrates. The addition of water into [Ch]­[Lys] did not exert a negative effect on pretreatment effectiveness, although the delignification capacity of the IL decreased. The sugar yields of 80% for glucose and 84% for xylose were obtained in the enzymatic hydrolysis after the sugar cane bagasse without size reduction was pretreated with a biomass loading of 5 wt % by 50 g 50% [Ch]­[Lys]–water mixture at 90 °C for 6 h. A simple and atom-economic preparation approach to ILs was successfully developed for lignocellulosic biomass pretreatment, which may significantly reduce ILs costs, and the reactant contaminations in the IL–water mixture had no detrimental effect on the pretreatment efficiency

Efficient Pretreatment of Wheat Straw Using Novel Renewable Cholinium Ionic Liquids To Improve Enzymatic Saccharification

Nine cholinium ionic liquids (ILs) were synthesized. A high solubility of lignin (up to 483 mg g^–1) and xylan (up to 721 mg g^–1) was observed in four ILs containing organic anions, while cellulose, chitosan, and keratin were scarcely soluble in all ILs. These ILs were used for wheat straw pretreatment. Among the nine ILs tested, cholinium taurate ([Ch]­[Tau]) was the best. The effects of biomass particle sizes, water contents, and biomass loadings on the IL pretreatment were studied. Readily digestible residues were obtained after wheat straw up to 2 mm size was pretreated. Additionally, this IL pretreatment process was highly tolerant toward moisture. A good reducing sugar yield (79.7%) was achieved in the enzymatic hydrolysis of wheat straw pretreated by [Ch]­[Tau] at a biomass loading of 10% under 80 °C for 6 h. Therefore, renewable sulfonate-based cholinium ILs may be promising solvents for pretreatment and fractionation of lignocelluloses

Utilization of Seawater for the Biorefinery of Lignocellulosic Biomass: Ionic Liquid Pretreatment, Enzymatic Hydrolysis, and Microbial Lipid Production

The biorefineries of lignocellulosic biomass have attracted increasing interest recently. However, large water consumption in the large-scale biorefineries remains a major problem. In this work, utilization of abundant seawater as an alternative to freshwater for ionic liquid (IL) pretreatment of lignocellulosic biomass was reported for the first time. In addition, enzymatic hydrolysis of IL-pretreated biomass and microbial lipid production from wheat straw hydrolysate were conducted in seawater. It was found that seawater had no significantly negative effect on enzymatic hydrolysis as well as IL pretreatment. After grass lignocelluloses were pretreated by 50% cholinium IL–seawater mixtures at 90 °C for 6 h and washed by seawater, the residues became highly susceptible to enzymatic hydrolysis; the reducing sugar yields of 54–72% were obtained in pH 4.8 seawater in the subsequent enzymatic hydrolysis of the residues. The lipid yield of 4.5 g/L and lipid coefficient of 0.21 g/g of sugar were achieved after cultivation of <i>Trichosporon fermentans</i> on wheat straw hydrolysate with the sugar concentration of approximately 30 g/L for 3 days

Biocatalytic Upgrading of 5‑Hydroxymethylfurfural (HMF) with Levulinic Acid to HMF Levulinate in Biomass-Derived Solvents

Valorization of biomass-based platform chemicals into high value-added products has attracted increasing attention recently. In this work, upgrading of 5-hydroxymethylfurfual (HMF) and levulinic acid, two important biomass-based platform chemicals, to HMF levulinate via a green and efficient enzymatic approach was reported. Novozym 435 was found to be the best biocatalyst for the enzymatic esterification. The enzymatic esterification progressed smoothly in <i>t</i>-butanol, 2-methyl-2-butanol, and cyclopentyl methyl ether as well as in the ecofriendly biomass-derived 2-methyltetrahydrofuran (2-MeTHF), while no enzymatic reaction occurred in deep eutectic solvents. When HMF concentration was up to 500 mM, a good conversion of 72% was achieved in 2-MeTHF. The reaction temperature exerted a significant effect on the enzymatic esterification. When the reaction temperature is below 40 °C, high HMF conversions (>85%) were obtained. Besides, significant inactivation of the enzyme was observed at more than 50 °C, resulting in poor conversions

Correlation between Physicochemical Properties and Enzymatic Digestibility of Rice Straw Pretreated with Cholinium Ionic Liquids

Ionic liquid (IL)-based lignocellulosic biomass pretreatment has attracted growing interest recently. In this work, cholinium ILs, a type of bio ILs composed totally of renewable biomaterials, were used to pretreat rice straw, and various physicochemical properties of the pretreated biomass including the morphological structure, biomass composition, biomass crystallinity, surface area and pore volume were studied. These physicochemical properties were correlated with the polysaccharide enzymatic digestibility (21–99% for cellulose and 9–83% for xylan). All the physicochemical properties examined exerted significant effects on the enzymatic hydrolysis of rice straw. Among these physicochemical features, surface area and pore volume were the principal factors affecting the polysaccharide digestibility. These physicochemical properties appeared to be intercorrelated, which could be converted into a linearly uncorrelated variable (the first principal component, PC1) by principal component analysis (PCA). PC1 proved to be a good predictor of the enzymatic digestibility of the pretreated rice straw, because there existed a closely positive linear correlation between the cellulose digestibility and PC1 score

Cell viability of <i>Candida parapsilosis</i>.

<p>Conditions: Cells were exposed to co-solvent systems comprising 10% (v/v) of various ILs and TEA-HCl buffer (100 mmol/L, pH 5.0), with and without substrate (3.0 mmol/L TMSB).</p

Effect of buffer pH on the bioreduction of TMSB.

<p>Symbols: (△) the initial reaction rate; (□) the maximum product yield; (○) the product <i>e.e.</i> All products have the (<i>S</i>) configuration. Reaction conditions: 3.0 mmol/L TMSB, 4.0 mL TEA-HCl buffer (100 mmol/L, various pH) containing 10% (v/v) C₂OHMIM·NO₃, 65.3 mmol/L 2-propanol, and 0.15 g/mL immobilized <i>C. parapsilosis</i> cells, 30°C, 180 r/min.</p

Effect of co-substrate concentration on the bioreduction of TMSB with immobilized <i>Candida parapsilosis</i> cells.

<p>Reaction conditions: 3.0 mmol/L TMSB, 4.0 mL TEA-HCl buffer (100 mmol/L, pH 5.0) containing 10% (v/v) C₂OHMIM·NO₃, various concentrations of 2-propanol, and 0.15 g/mL immobilized <i>C. parapsilosis</i> cells, 30°C, 180 r/min.</p