Synthesis of Biodegradable Hydrogel by Radical Ring‐Opening Polymerization of 2‐Methylene‐1,3,6‐Trioxocane

2‐Methylene‐1,3,6‐trioxocane (MTC), maleic anhydride (MA), and poly(ethylene glycol diacrylate) 400 (PEGD) or divinyl adipate (DVA) were terpolymerized in the presence of a radical initiator. Though the obtained gels did not absorb deionized water, the gels could absorb deionized water and saline after hydrolyzing the MA carboxylate anhydride functionality. The absorbing ratios of deionized water and saline were high. The biodegradability of the hydrogels after hydrolysis was found to be good by a biochemical oxygen demand (BOD)‐tester using soil.     

玉米塑料——第四类化学新材料

玉米塑料作为一种新型生物质材料,因其优越的性能被誉为"第四类化学新材料",本文试从玉米塑料的研发、生产意义及应用前景等方面加以介绍。     

Crystallization behavior, thermal property and biodegradation of poly(3-hydroxybutyrate)/poly(ethylene glycol) grafting copolymer

The poly(3-hydroxybutyrate)(PHB)/poly(ethylene glycol)(PEG) grafting copolymer was successfully prepared by PHB and acrylate groups ended PEGM using AIBN as initiator. The crystallization behavior, thermal stability and environmental biodegradability of PHB/PEG grafting copolymers were investigated with differential scanning calorimetry (DSC), Thermogravimetric analysis (TGA), wide angle X-ray diffraction (WAXD), scanning electron microscopy (SEM), and Biodegradation test in vitro. In the results, all the grafting copolymers were found to show the X-ray diffraction arising from the PHB crystal lattice, while none of the PEG crystallized peaks could be found even though the graft percent reached 20%. This result indicated that PEG molecules were randomly grafted onto PHB chain. The thermal properties measured by DSC showed that the melting temperature(T_m) and glass transition temperature (T_g) were both shifted to lower temperature with the graft percent increasing, and this broadened the narrow processability window of PHB. According to TGA results, the thermal stability of the grafting copolymers is not changed compared to pure PHB. From the biodegradation test, it could be concluded that degradation occurred gradually from the surface to the inside and that the degradation rate could be adjusted by the PEG grafting ratio. In another words, the biodegradation profiles of PHB/PEG grafting copolymer can be controlled. These properties make PHB/PEG grafting copolymer have promising potential applications especially in agriculture fields.     

Production of Biodegradable Polymer from Agro-Wastes in Alcaligenes sp. and Pseudomonas sp.

The present study was aimed to evaluate the suitability of agro-wastes and crude vegetable oils for the cost-effective production of poly-β-hydroxybutyrate (PHB), to evaluate growth kinetics and PHB production in Alcaligenes faecalis RZS4 and Pseudomonas sp. RZS1 with these carbon substrates and to study the biodegradation of PHB accumulated by these cultures. Alcaligenes faecalis RZS4 and Pseudomonas sp. RZS1 accumulates higher amounts of PHB corn (79.90% of dry cell mass) and rice straw (66.22% of dry cell mass) medium respectively. The kinetic model suggests that the Pseudomonas sp. RZS1 follows the Monod model more closely than A. faecalis RZS4. Both the cultures degrade their PHB extract under the influence of PHB depolymerase. Corn waste and rice straw appear as the best and cost-effective substrates for the sustainable production of PHB from Alcaligenes faecalis RZS4 and Pseudomonas sp. RZS1. The biopolymer accumulated by these organisms is biodegradable in nature. The agro-wastes and crude vegetable oils are good and low-cost sources of nutrients for the growth and production of PHB and other metabolites. Their use would lower the production cost of PHB and the low-cost production will reduce the sailing price of PHB-based products. This would promote the large-scale commercialization and popularization of PHB as an ecofriendly bioplastic/biopolymer.     

利用衰减全反射傅里叶红外光谱(ATR-FTIR)技术快速筛选可降解苯酚菌株

苯酚是一种重要的化工原料并广泛存在于工业废水中,随着各国对苯酚生物毒性的认识,排放标准日益提高。生物法作为一种高效、 低成本、 不易二次污染的方法常用于含酚的废水处理。但是可降解苯酚的微生物筛选却是一个复杂繁琐的过程。衰减全反射傅里叶红外光谱(attenuated total reflection Fourier transform infrared,ATR-FTIR)技术是一种高效、 快捷、 高指纹特性的物理检测技术,主成分分析联用最小偏二乘法(principal component analysis-partial least squares,PCA-PLS)是一种有效提取特征指纹峰并建立模型的方法,该实验联合ATR-FTIR检测技术和PCA-PLS统计方法建立苯酚浓度与吸光度模型,可以快速检测固体培养基中底物浓度。实验建立模型判定系数可以达到99.5%,预测集的判定系数可以到达99.4%,说明模型具有较高的拟合性和推广性。通过模型可以预测出菌株降解后固体培养基底物浓度,筛选出可降解苯酚功能微生物,传统的液体培养并采用气相色谱检测残留苯酚浓度筛选出的结果与ATR-FTIR方法筛选出结果进行对比发现,得到相同的筛选结果。结果表明ATR-FTIR联合PCA-PLS建立高拟合度模型,可以快速检测固体培养基底物浓度,从而达到快速筛选可降解苯酚菌的目的,这种方法可以应用到其他有特征指纹峰的底物中,ATR-FTIR是一种可以广泛应用到功能微生物筛选的快速检测方法。     

Bioplastic biodegradation activity of anaerobic sludge prepared by preincubation at 55 °C for new anaerobic biodegradation test

The new method to evaluate the anaerobic biodegradability of bioplastics, such as polycaprolactone (PCL) and poly (lactic acid) (PLA), under aquatic (slurry) conditions at 55 °C is applying. For this method, we prepared the sludge at 55 °C from the sludge at 37 °C by the method in which the sludge from the real tank operating at around 37 °C using cow manure and vegetable waste as the feed stock was preincubated at 55 °C. It was unknown at which stage the sludge during preincubation has the optimized anaerobic biodegradation activity of plastics. Four different stage sludges during preincubation (the sludge at 7 days after the start of preincubation at 55 °C, at 12 days, at 18 days, and at 40 days) were compared by the anaerobic biodegradation activity of PLA. The preincubated sludge at around 18 days (a gradual decrease in biogas evolution and a methane ratio over 60%) showed the highest biodegradation activity of PLA. In addition, the bacterial population in each sludge was analyzed by the denaturing gradient gel electrophoresis (DGGE) analysis of the amplified 16S rRNA gene fragments, however, the newly grown bacteria bands at 55 °C were not clearly detected.     

Degradation of Perfluorooctane Sulfonamide by Acinetobacter Sp. M and Its Extracellular Enzymes

The Acinetobacter sp. strain M isolated from a contaminated soil sample in Jiangsu Province of China was found to be able to degrade perfluorooctane sulfonamide (PFOSA) effectively. Fluoride anion (F^?) released from PFOSA degradation was detected by ion chromatography, and showed positive correlation to the growth curve of Acinetobacter sp. strain M. The PFOSA degradation efficiency of strain M was approximately 27 %, as assessed by GC analysis. It was shown that enzymes localized outside of cells of Acinetobacter sp. strain M catalyzed the degradation of PFOSA. This further indicates a possibly new (multi‐step/pathway) mechanism for PFOSA degradation. It revealed that the extracellular enzyme of the Acinetobacter strain M preferentially cleaves carbon‐carbon and carbon‐fluorine bonds instead of destroying the carbon‐sulfur bond. The growth condition for Acinetobacter sp. strain M was optimized at 30 °C and pH 7.0 in the presence of 2000 mg L^?1 of PFOSA and 0.5 % (v/v) of Tween‐20. The optimal PFOSA degradation time was found to be 12 h, with a degradation efficiency of 76 % by extracellular enzymes in strain M as determined by GC analysis. The result may provide potential applications for biodegradition of perfluoro organic compounds, such as derivatives of perfluorooctane (C8).     

Biodegradable Ultrasmall‐in‐Nano Gold Architectures: Mid‐Period In Vivo Distribution and Excretion Assessment

The persistence of metals in the body after the designed theranostic action has hampered the clinical translation of noble metal nanoparticles (NPs) to clinics. Therefore, the appealing behaviors of NPs for healthcare applications are still on the bench‐side. Here, quantitative evaluation in healthy murine models show that gold comprised in passion fruit‐like nanoarchitectures (NAs) are excreted daily over a 10 d period by both renal and biliary pathways after biodegradation to the building blocks. Furthermore, histological analyses confirm the absence of nephrotoxicity and the remarkable biocompatibility of NAs up to the higher tested amount of 150 mg kg^?1. These in vivo findings demonstrate that NAs are the first full‐inorganic disassembling nanoplatforms exhibiting a noticeable excretion rate from model organisms. Such results are a significant step in bringing noble metal nanotheranostics to the forefront of cancer treatments once again.     

Biotransformation of butyltin compounds using pure strains of microorganisms

The debutylation of tributyltin chloride by several strains of fungi, yeasts and bacteria is described. Under standard conditions and with low initial concentration of substrate, significant biotic degradation of tributyltin (6–32%) was detected after five days at 28°C. Dibutyltin and monobutyltin were formed in all cases, with higher yields of the latter. Two microorganisms catalysed the transformation of monobutyltin to dimethyltin and trimethytin whereas all microorganisms were able to methylate inorganic tin(IV) to trimethyltin. Our results suggest that tributyltin biodegradation by microorganisms is generally possible, provided sufficiently low concentrations of substrate are used.