The growth of oleaginous Rhodotorula glutinis in an internal-loop airlift bioreactor by using mixture substrates of rice straw hydrolysate and crude glycerol

The conversion of lignocellulosic biomass (LCB) to microbial oils is attracting a growing amount of attention. However, the growth of the oleaginous yeast Rhodotorula glutinis on LCB hydrolysate (mainly rice straw) only will lead to a low lipid mass fraction, in the range of 10–20%. This study shows that the addition of crude glycerol to the LCB hydrolysate medium can efficiently raise the lipid mass fraction to the range of 30–40%. Crude glycerol is a by-product in the biodiesel production process. The use of renewable LCB hydrolysate and crude glycerol would greatly reduce the substrate cost for microbial oil production using R. glutinis. In addition, the results of experiments show that a low-cost airlift bioreactor is a more suitable fermentation process for the growth of R. glutinis than the use of a conventional agitation tank. When using mixed carbon sources of LCB hydrolysate with 30 kg m⁻³ of reducing sugars and 30 kg m⁻³ of crude glycerol, a maximal cell mass of 21.4 kg m⁻³ and lipid mass fraction of 58.5 ± 6.2 were achieved in an internal loop airlift bioreactor, and this process may have the potential to be applied in scale-up production.     

溶剂对环氧乙烷催化水合制乙二醇的影响

研究了NY催化剂催化环氧乙烷水合制乙二醇(EG)过程中,溶剂、催化剂添加量和水与环氧乙烷的摩尔比(简称水比)对EG选择性的影响。实验结果表明,以丙三醇作为溶剂使催化剂进行循环,能提高EG的选择性,效果好于以生成的EG作为溶剂循环催化剂。催化剂添加量、水比和溶剂添加量对EG选择性具有较大影响,其中溶剂添加量对EG选择性的影响最显著。在低水比(1.0~4.0)条件下,EG质量分数小于30%、催化剂质量分数大于7.2%时,EG选择性稳定在95.63%~97.92%,平均值为96.80%,此结果对于进一步降低EG合成工艺的能耗具有指导意义。     

Effect of Particle Size on Monometallic and Bimetallic (Au,Pd)/C on the Liquid Phase Oxidation of Glycerol

The influence of metal particle size of monometallic and bimetallic supported catalysts (Au, Pd, Au–Pd)/C was studied using as a model reaction the liquid phase oxidation of glycerol. By tuning the metal particle size from 2 to 16 nm a progressive decrease of activity and simultaneously an increase in the selectivity to sodium glycerate was observed. Moreover, the influence of the temperature was studied and it was found that by increasing the temperature, only with a large particle size the formed glycerate was retained and not over-oxidized to tartronate.     

环氧氯丙烷下游产品生产现状及市场前景

论述了环氧氯丙烷的主要下游产品环氧树脂、合成甘油、氯醇橡胶等的生产现状、市场前景等,指出:我国氯碱行业应该重视这些环氧氯丙烷下游精细化工产品的开发,以促进我国环氧氯丙烷的发展。     

以葡萄糖为辅助底物发酵生产1,3-丙二醇的研究

采用Klebsiellapneumoniae对葡萄糖作为辅助底物发酵生产 1 ,3 丙二醇进行了研究。结果表明葡萄糖单独作为底物发酵时不生成 1 ,3 丙二醇。以葡萄糖和甘油为混合底物时 ,则可以显著提高菌体浓度 ,但是 1 ,3 丙二醇浓度和甘油到 1 ,3 丙二醇转化率没有提高。在甘油为底物的批式发酵过程中 ,通过流加葡萄糖作为辅助底物可以提高甘油到 1 ,3 丙二醇的摩尔转化率 ,同时可缩短发酵时间。通过选择合适的葡萄糖流加速率 ,较以甘油为单一底物的发酵结果 ,1 ,3 丙二醇的摩尔转化率最高可达0 649,提高了 53 4% ;生产强度为 1 0 0 5g/ (L·h) ,提高了 1 39 9%。     

Chemo-enzymatic synthesis of amino acid-based surfactants

The application of lipases to the synthesis of amino acid-based surfactants was investigated. Low yields (2–9%) were obtained in the acylation of free amino acids, such as l-serine and l-lysine, as well as their ethyl esters and amides with fatty acids, owing in part to low miscibility of the reactants. When the N-carbobenzyloxy (Cbz)-l-amino acids were used in an effort to improve miscibility of the amino acid derivatives with the acyl donor, a dramatic improvement was observed for N-Cbz-l-serine (92% yield) but not for N _α-Cbz- or N _ζ-Cbz-l-lysine (7 and 2% yield, respectively). As an alternative, and efficient synthesis of N _ζ-acyl-l-lysines was developed, based on the regiospecific chemical acylation of copper(II) lysinate. In pursuit of a general route to amino acid-fatty acid surfactants, the utility of a polyol linker was investigated. Thus, the glycerol ester of N _α′ N _ζ-di-Cbz-l-lysine was prepared and evaluated as a substrate for acylation. As expected, this and other glycer-1-yl esters of N-protected amino acids were excellent substrates for lipase-catalyzed acylation. Their reaction with myristic acid in the presence of Novozyme resulted in the regioselective acylation of the primary hydroxyl group of the glycerol moiety to afford the corresponding 1-O-(N-Cbz-l-aminoacyl)-3-O-myris-toylglycerols with conversions of 50–90%. These were readily deprotected to give a range of 1-O-(aminoacyl)-3-O-myristoyl-glycerols with overall yields of 27–71%.     

Single-phase gold/palladium catalyst: The nature of synergistic effect

The liquid phase oxidation of glycerol with oxygen has been studied using mono and bimetallic catalysts based on Au and Pd metals supported on activated carbon, in order to study the effect of the metal on the distribution of the products and on activity of catalysts. It was found that by using bimetallic catalysts (Au–Pd) a strong synergistic effect was shown. By using a preformed nucleating centre we were able to obtain a single alloyed phase, which allowed us to address the synergistic effect to the presence of alloyed Au/Pd. The advantage of using this latter catalyst lies not only in the high activity but also in a prolonged catalyst life. Although a partial leaching of palladium and assembling of the particles have been revealed by ICP and HRTEM respectively, activity after 10 re-cycles decreased less than expected (about 10%).     

复合固体超强酸SO42-/ZrO2-TiO2催化合成三醋酸甘油酯

采用复合固体超强酸SO₄^2-/ZrO₂-TiO₂为催化剂，甘油和冰醋酸为原料，结合醋酸精馏回流工艺，合成了三醋酸甘油酯（TCG）。通过对合成工艺改进，免除了有毒带水剂的使用。使TCG合成更安全，更经济和环保。催化剂制备和TCG合成最佳工艺条件为：硫酸浸渍液浓度（0.5～0.55） mol·L^－1，焙烧温度（550～600） ℃，催化剂用量（占总投料量质量分数）2.5％～3.0%。投料比n（甘油）∶n（醋酸）=1∶ 5.5，反应温度130 ℃，反应时间3.0 h，产品收率达92.6%，催化剂可重复使用6次，易于再生。