A Bi-Enzymatic Cascade Pathway towards Optically Pure FAHFAs**

Recently discovered endogenous mammalian lipids, fatty acid esters of hydroxy fatty acids (FAHFAs), have been proved to have anti-inflammatory and anti-diabetic effects. Due to their extremely low abundancies in vivo, forging a feasible scenario for FAHFA synthesis is critical for their use in uncovering biological mechanisms or in clinical trials. Here, we showcase a fully enzymatic approach, a novel in vitro bi-enzymatic cascade system, enabling an effective conversion of nature-abundant fatty acids into FAHFAs. Two hydratases from Lactobacillus acidophilus were used for converting unsaturated fatty acids to various enantiomeric hydroxy fatty acids, followed by esterification with another fatty acid catalyzed by Candida antarctica lipase A (CALA). Various FAHFAs were synthesized in a semi-preparative scale using this bi-enzymatic approach in a one-pot two-step operation mode. In all, we demonstrate that the hydratase-CALA system offers a promising route for the synthesis of optically pure structure-diverse FAHFAs.     

Metaproteomic analysis of enzymatic composition in Baobaoqu fermentation starter for Wuliangye baijiu

Wuliangye is one of the most famous brands of baijiu in China. The typical flavours of Wuliangye baijiu are mainly formed by the multifarious enzymes in fermentation starter (Baobaoqu, BBQ). As the enzymes remained poorly understood, the detailed enzymatic composition of BBQ was analysed by metaproteomics for the first time. It is worth noting that the enzymes from plant, animals and micro-organisms were detected together and oxidoreductases were the dominant enzymes. Next, the analysis of function showed that the enzymes were mainly involved in carbon metabolism and the biosynthesis of amino acids. Additionally, the relationship between differential abundant enzymes and formation of typical flavour substances in premium and normal BBQ was established. Furthermore, the activities of classic enzymes in BBQ were examined to verify the reliability of metaproteomic results. This study will provide clues to further improve the manufacturing technology for Wuliangye baijiu.     

鲟鱼肝酶解条件优化及酶解液对双歧杆菌增殖效果的研究

为提高鲟鱼肝脏的加工附加值，使用碱性蛋白酶，以水解度为评价指标，在单因素试验的基础上，通过Plackett-Burman试验、响应面分析法优化鲟鱼肝蛋白酶解条件。在此条件下，进一步探究了酶解液对双歧杆菌的促生长效果。结果表明，最优酶解条件为碱性蛋白酶添加量10 540 U/g鱼肝蛋白、体系初始pH值10.0、酶解时间8.6 h、酶解温度45 ℃、料液比1∶10（g∶mL），此条件下水解度（81.7%）是优化前（40.4%）的1.02倍。鲟鱼肝蛋白酶解液对青春双歧杆菌、两歧双歧杆菌、动物双歧杆菌、长双歧杆菌、短双歧杆菌和婴儿双歧杆菌6种均具有显著的促生长效果。研究结果为鲟鱼加工副产物利用提供了新途径，同时也为双歧杆菌促生长因子的研发提供新思路。     

Aqueous One-pot Synthesis of Glycopolymers by Glycosidase-catalyzed Glycomonomer Synthesis Using 4,6-Dimetoxy Triazinyl Glycoside Followed by Radical Polymerization

Glycopolymers have attracted increased attention as functional polymeric materials, and simple methods for synthesizing glycopolymers remain needed. This paper reports the aqueous one-pot and chemoenzymatic synthesis of four types of glycopolymers via two reactions: the β-galactosidase-catalyzed glycomonomer synthesis using 4,6-dimetoxy triazinyl β-D-galactopyranoside and hydroxy group-containing (meth)acrylamide and (meth)acrylate derivatives as the activated glycosyl donor substrate and as the glycomonomer precursors, respectively, followed by radical copolymerization of the resulting glycomonomer and excess glycomonomer precursor without isolating the glycomonomers. The resulting glycopolymers bearing galactose moieties exhibited specific and strong interactions with the lectin peanut agglutinin as glycoclusters.     

Assessment of toxic content in Balanites aegyptiaca seed cake and use of enzymatic-catalysed biodiesel in diesel engine

The present study deals with the estimation of toxic phorbol esters in Balanites aegyptiaca seed cake and to evaluate the performance and combustion characteristics of different blends of biodiesel in a diesel engine. The seeds were manually collected from arid regions of Rajasthan, India and the oil extracted from the powdered kernel with Solvent extraction process. The extracted oil processed by enzymatic catalytic reactions are carried out at optimum operating conditions such as the molar ratio of 8:1 (methanol:oil), reaction temperature at 40°C for 4?h reaction time and xylanase 1% based on oil weight. The total conversion rate of extracted oil to methyl ester by enzymatic reactions yields up to 98.3%. The toxic content of seed cake was determined by high-performance liquid chromatography (HPLC, Shimadzu). The performance and combustion parameters such as BP, BTE and CP decreased, whereas BSFC and DP increased with biodiesel blends.     

Optimization of selective acidolysis pretreatment for the valorization of wheat straw by a combined chemical and enzymatic process

The cover image is based on the Original Article Optimization of selective acidolysis pretreatment for the valorization of wheat straw by a combined chemical and enzymatic process by Yong Xu, Jianming Guo, Shizhong Zhang et al., https://doi.org/10.1002/jctb.6251 .

     

Post‐polymerization modification of bio‐based polymers: maximizing the high functionality of polymers derived from biomass

The renaissance of the bio‐based chemical industry over the last 20 years has seen an ever growing interest in the synthesis of new bio‐based polymers. The building blocks of these new polymers, so called platform molecules, contain significantly more chemical functionality than their petrochemical counterparts (such as ethene, propene and para‐xylene). As a result bio‐based polymers often contain greater residual chemical functionality in their chains, with groups such as alkenes and hydroxyls commonly observed. These functional groups can act as sites for post‐polymerization modification (PPM), thus further extending the range of applications for bio‐based polymers by tailoring the polymers' final properties. This mini‐review highlights some of the most recent and compelling examples of how to make use of bio‐based polymers with residual functional groups for PPM. It also looks at how the emerging interdisciplinary field of enzymatic polymer synthesis allows for increased functionality in polymers by avoiding side‐reactions as a result of milder reaction conditions, and additionally offers an alternative means of polymer surface modification. © 2018 Society of Chemical Industry     

新型嗜热耐碱脂肪酶的纯化表征及应用

将来源于解脂嗜热互营杆菌（Thermosyntropha lipolytica）的脂肪酶（TlLipA）基因tll1导入大肠杆菌BL21（DE3）中表达，通过热处理和镍柱亲和层析获得纯酶，并对其酶学性质进行研究。十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE）显示TlLipA分子量为53×10³，其最适反应温度为65℃，最适反应pH为8.0。在55~65℃范围内酶活较高且比较稳定；在pH^{7.0~11.0于室温保存1 h后，残留相对酶活仍达80%以上。1 mmol/L 金属离子Zn2+、Fe3+和试剂SDS，0.05%（质量分数）Tween 80，对酶活力具有强烈的抑制作用，残留相对酶活皆低于15%；1 mmol/L Mg2+、Mn2+对酶活力表现出轻微的激活作用。由底物专一性实验可得，该酶对辛酸对硝基苯酯（C8）和癸酸对硝基苯酯（C10）偏好明显。以棕榈酸对硝基苯酯（p-NPP）为底物，该酶动力学参数K_m值为0.23 mmol/L，V_max为33.50 mmol/(L·min)，k_cat为22.83 _S-1。以重组脂肪酶为催化剂在无溶剂体系中制备生物柴油，含水率20%，酶加量200 U/g油，醇油比为4∶1的条件下，在55℃催化大豆油反应48 h，收率可达91.75%。}     

Synthesis and Characterization of 2-monoacylglycerols from Canarium Oil (Canarium Indicum)

This paper studies synthesis and characterization of 2-monoacylglycerols (2-MAGs), generally used for structured lipid production. Synthesis used canarium oil by enzymatic reaction using immobilized lipase from Mucor miehei that has a specific activity on the sn-1 and 3 of the triacylglycerol structure. Characterization of 2-MAGs by thin layer chromatography using a standard of 2-oleoylglycerol followed by isolation and purification to determine the fatty acids composition.The highest composition of fatty acids on 2-MAGs were unsaturated fatty acids, namely oleic acid (939.8 ppm) and linoleic acid (445.5 ppm), therefore it could be used for the synthesis of structured lipid.