Highly efficient production of 2,5-dihydroxymethylfuran from biomass-derived 5-hydroxymethylfurfural over an amorphous and mesoporous zirconium phosphonate catalyst

The development of high-efficiency and low-cost catalysts is very crucial for the MeerweinPonndorf-Verley (MPV) reduction of biomass-derived 5-hydroxymethylfurfural (HMF) into 2,5-dihydroxymethylfuran (DHMF). In this work, an amorphous and mesoporous zirconium phosphonate catalyst (Zr-DTMP), which is a zirconium-containing organic-inorganic nanohybrid, was successfully designed and synthesized by the simple assembly of zirconium tetrachloride (ZrCl4) and diethylene triaminepenta(methylene phosphonic acid)(DTMP). Satisfactorily, when Zr-DTMP was employed for the MPV reduction of HMF in the presence of 2-butanol (secBuOH), DHMF yield could be achieved as 96.5% in 3 h under a relatively mild reaction temperature of 140℃. Systematic investigations indicated that this high catalytic activity should be mainly due to the cooperative role of enhancive Lewis acid site (Zr4+) and Lewis base site (O2-) in activating the carbonyl group of HMF and dissociating the hydroxyl group of secBuOH, respectively. Additionally, Zr-DTMP showed excellent catalytic stability, when it was successively used 5 recycles, its surface characteristics and textural properties still remained almost unchanged, and so, the catalytic activity was not obviously affected. More interestingly, Zr-DTMP could also be applied for the selective reduction of other biomass-derived carbonyl compounds, such as 5-methylfurfural (MF), furfural (FF), levulinic acid (LA), ethyl levulinate (EL) and cyclohexanone (CHN), into the corresponding products with high yields, which is beneficial to the effective synthesis of various valuable bio-based chemicals.

Identifying peptides that specifically bind to MDA-MB-468 breast cancer cells

Objective To use phage display technique to screen for small polypeptides that specifically bind to MDA-MB-468 cells.Methods A random heptapeptide phage display library was used for in vitro screening against target MDA-MB-468 cells.SC1180 cells were used for subtractive selection.High-affinity phage DNA was extracted,and peptides were sequenced.Results(1)The original library capacity of the polypeptide library was 2×10^13 pfu/mL,and phage titer was determined over 4 rounds.The average library capacity was 1.8×10^13 pfu/mL.(2)Subtractive screening showed that the phage library volume of each round was 1.8×10^12 pfu/mL,and that there was an enrichment effect in each subsequent round.Screening was stopped after the fourth round.(3)PCR results showed that the size of 39 products(78.0%)and 11 products(22%),were 300 bp and 258 bp,respectively.Thirty positive phages were selected for DNA extraction and sequencing,and the corresponding amino acid sequence was LMTRXSK.The sequence had no homology with known genes or proteins.Conclusion Using the phage display technique,we identified that the short polypeptide,LMTRXSK,specifically binds MDA-MB-468 human breast cancer cells.

Total Synthesis of （＋）-Chinensiolide B from α-Santonin

A short and efficient total synthesis of （＋）-chinensiolide B is reported, starting from commercially available a-santonin, This strategy could be used for rapid preparation of chinensiolides and their derivative for further structure activity relationship studies.

A comprehensive evaluation of re-circulated bio-filter as a pretreatment process for petroleum refinery wastewater

Conventional biological treatment process is not very efficient for the treatment of petroleum refinery wastewater （PRW） that contains high-concentration of organic contaminants. Prior to biological treatment, an additional pretreatment process for PRW is required for the effluent to meet the discharge standards. While re-circulated bio-filter （RBF） has been applied as a pretreatment process in several PRW treatment plants, its effects have not been comprehen- sively evaluated. In this study, the parameters of operation, the changes in pollution indexes and contaminant composition in an engineered RBF have been investigated. We found that mainly highly active de-carbonization bacteria were present in the RBF, while no nitrification bacteria were found in the RBF. This indicated the absence of nitrification in this process. The biodegradable organic contaminants were susceptible to degradation by RBF, which decreased the Biological Oxygen Demand （BODs） by 83.64% and the Chemical Oxygen Demand （CODcr） by 54.63%. Consequently, the alkalinity and pH value of RBF effluent significantly increased, which was unfavorable for the control of operating parameters in subsequent biological treatment. Along with the decrease of CODcr, the RBF effluent exhibited a reduction in biodegradability. 834 kinds of recalcitrant polar organic contaminants remained in the effluent; most of the contaminant molecules having complex structures of aromatic, polycyclic and heterocyclic rings. The results of this study showed that RBF could efficiently treat PRW for biodegradable organic contaminants removal; however, it is difficult to treat bio-refractory organic contaminants, which was unfavorable for the subsequent biological treatment process operation. An improved process might provide overall guarantees for the PRW treatment.