乙醇降解乳酸菌的筛选、鉴定及解酒防醉功效评价

该研究采用传统培养分离法从传统发酵食品奶疙瘩样品中分离乳酸菌,通过体外降解乙醇试验筛选高效降解乙醇功能的菌株,通过形态学观察、生理生化实验及分子生物学技术对其进行菌种鉴定,并对其进行安全性评价、耐逆性试验,以及体内小鼠防醉解酒功效试验。结果表明,筛选鉴定出一株乙醇降解率高(13.38%)、乙醇耐受能力强(耐受体积分数12%乙醇)的乳酸片球菌(Pediococcus acidilactici)RH2712,其对氨苄西林、青霉素、亚胺培南、氯霉素敏感,溶血性安全;对酸和胆盐耐受力强,在pH 3.0的条件下活菌对数值几乎不变,延迟时间为2 h,在1.5%胆盐含量下培养4 h后活菌对数值达到8.72,延迟时间仅为0.5 h,在人工模拟胃液条件下处理3 h后活菌对数值仍能达到7.14。乳酸片球菌RH2712在小鼠试验中表现出明显的防醉解酒的功效,且活菌数为1×10^(8)~1×10^(9)CFU/m L时解酒功能强于美他多辛。

一株乙醇降解菌株的筛选、鉴定及其培养条件的优化

从酸败的酒糟中筛选出降解乙醇能力强的菌株,并优化其培养条件。根据菌株的形态、生理生化特征和16S rDNA基因序列分析对筛选菌株进行鉴定,通过正交试验等优化手段提高菌株产酶能力。结果表明,从酸败的酒糟中筛选得1株降解乙醇能力相对较高的巴氏醋杆菌(Acetobacter pasteurianus)Ⅶ,其乙醇降解能力为0.72 mL/d;正交试验得该菌株培养的最佳培养基组成为0.5%牛肉膏、1.0%蛋白胨、0.3%NaCl、8%无水乙醇(V/V)、0.1%K2HPO4.3H2O、0.05%MgSO.47H2O、0.001%FeSO.47H2O,pH 7.0。耐乙醇驯化后,Ⅶ号菌株对乙醇的降解能力提高至2.3 mL/d。

乙醇降解菌种的筛选及其发酵乳产品解酒功效评价

通过乙醇耐受度、乙醇降解能力测定,从10株发酵性能良好的乳酸菌中筛选出乙醇降解效果好的菌种,并评价此菌种生产的发酵乳产品的体内外解酒功效。结果表明,筛选出1株具有高效乙醇降解能力的嗜酸乳杆菌,用其复配发酵菌种生产的发酵乳产品在模拟胃、肠液消化条件下,乙醇脱氢酶激活率分别为(36.87±1.58)%、(33.64±1.90)%,2,2’-联氮双(3-乙基苯并噻唑啉-6-磺酸)阳离子自由基清除能力(以谷胱甘肽当量计)分别为(1293.72±4.12)、(729.98±21.37)μmol/mL,1,1-二苯基-2-三硝基苯肼自由基清除能力(以谷胱甘肽当量计)分别为(16.14±0.12)、(11.26±0.10)μmol/mL;大鼠灌胃不同剂量发酵乳均能降低血液中乙醇质量浓度,高剂量组3 h后降为51.62 mg/100 mL(P<0.001),并能不同程度降低血清中谷丙转氨酶、谷草转氨酶活性且呈剂量依赖性,对乙醇所致肝损伤有较好的保护作用。研究为后续解酒功能性产品的研发提供科学依据。

罗汉果内生菌中乙醇降解菌株的筛选及其发酵条件优化

通过传统培养分离法从广西龙胜县的罗汉果植株中分离内生菌,通过乙醇耐受性测定和重铬酸钾-硫酸法从中筛选出对乙醇具有降解活性的菌株,通过形态观察及分子生物学技术对其进行鉴定,并以乙醇降解率为评价指标,采用单因素试验及正交试验对其发酵条件进行优化。结果表明,从罗汉果中分离得到68株内生菌,从中筛选到1株乙醇降解活性较高的菌株G-1,并被鉴定为尖孢镰刀菌(Fusarium oxysporum),其降解乙醇的最优发酵条件为马铃薯葡萄糖琼脂(PDA)培养基,初始pH值6.0,接种量7%,装液量200 mL/500 mL,发酵温度32℃,130 r/min条件下振荡培养3 d。在此优化条件下,乙醇降解率为29.77%,表明罗汉果内生菌具有降解乙醇的潜力。

嗜热厌氧纤维素降解产乙醇细菌的选育及发酵因子研究

从贡嘎山热温泉及土壤堆肥中分离到四株嗜热厌氧纤维素分解细菌，能直接转化纤维素生产酒精。其中一株经鉴定为热纤梭菌。对该菌发酵条件进行了研究，最适生产温度为５５－５８℃，最适起始ＰＨ值７．０．在实验室发酵最佳条件下，纤维素降解率最高可达８１％，乙醇产量最高为９７２ｍｇ／Ｌ（培养基纤维素含量为５ｇ／Ｌ．经紫外诱变选育到突变株，乙醇产量达２７４４ｍｇ／Ｌ，具有较好的乙醇耐受力。

Degradation of polyvinyl-alcohol wastewater by Fenton’s reagent: Condition optimization and enhanced biodegradability

The pretreatment of refractory polyvinyl-alcohol （PVA） wastewater with low value of CODcr by Fenton＇s reagent was investigated to enhance the biodegradabilily. The effects of operating conditions such as pH of the solution, Fe2＋ dosage, H2O2 dosage, reaction time and initial PVA concentration on the removal efficiency of CODCr were discussed. It is demonstrated that the optimum value of pH for removal of CODcr is 5 and the most suitable dosages of H2O2 （2%） and FeSO4 （10 mg/L） are 5% and 8.0%, respectively. When the initial CODcr value of the PVA water is 760 mg/L, the favorable reaction time is 110 min. Under these optimum conditions, the removal ratio of CODcr is 58.6% 61.4%, and the value of biodegradability （CODB/CODcr） increases markedly from 8.9% 9.7% to 62.6% 68.3%.

One-pot synthesis of poly vinyl alcohol(PVA) supported silver nanoparticles and its efficiency in catalytic reduction of methylene blue

Stable silver nanoparticles were synthesized using polyvinyl alcohol （PVA） as reducing and capping agent. The method of steric stabilization was adopted for the incorporation of silver nanoparticles in the polymer matrix. The successful incorporation of silver nanoparticles in a PVA matrix was confirmed by UV–Visible spectroscopy, transmission electron microscopy （TEM） and Fourier transform infrared （FT-IR） spectroscopy. The synthesized silver nanoparticles were characterized by a peak at 426 nm in the UV–Vis spectrum. TEM studies showed the formation of spherical shaped silver nanoparticles of 10-13 nm, following the reduction by UV irradiation. Catalytic properties were studied by means of UV-Visible spectroscopic analysis. The synthesized silver nanoparticles exhibited good catalytic properties in the reduction of methylene blue.

Degradation behaviors,thermostability and mechanical properties of poly(ethylene terephthalate)/polylactic acid blends

It is difficult for polyethylene terephthalate （PET） to degrade,which caused severe pollution.In this work,polylactic acid （PLA） was introduced to improve the degradation of PET.PET/PLA was synthesized by extrusion blending.The thermal,crystalline and mechanical properties of blends were investigated with TGA,DSC,WAXD and universal testing machine.The degradation of the blends in soil,acid and alkaline buffer solutions was assessed,respectively.It was found that the introduction of a little PLA promoted crystallization of PET during injection molding process.The starting decomposition temperature lowered from 412.1 ℃ of pure PET to 330.4 ℃ at 50% PLA content,tensile and bending strength of blends gradually decreased with the PLA content increasing,while the degradation rate improved.Alkaline environment was most beneficial for blends to degrade.The degradation mechanism was discussed.

可吸收骨折固定物的研究进展

可吸收骨折固定物作为有前途的生物固定材料,正日益受到重视,其研究在不断进展。本文重点综述了可吸收固定物实验与临床研究方面的文献,较全面地介绍了临床应用概况。

Mechanism of Photo-Fenton Degradation of Ethanol and PVA

Contrast degradation experiments between ethanol and polyvinyl alcohol (PVA) were conducted during H2O2, UV/H2O2, Fenton, and Photo-Fenton processes in this study. UV/VIS spectra showed' that complexes between Fe(Ⅲ) and organics were easily formed and degraded within reaction time. Compared with ,the degradation of complex, hydroxyl radicals acted weakly in Fenton or Photo-Fenton process. Hydroxyl radi'cals involved in Photo-Fenton process were deemed to be generated from the split decomposition of H2O2, photolysis of Fe_aq^3+, and degradation of hydrated Fe(Ⅳ)-complex but not traditional Fenton reaction. Experimental evidence to support this point was presented in this paper.

Biodegradation of DTP and PET Fiber by Microbe

The degradation of diethylene glycol terephthalate (DTP) and polyethylene terephthalate (PET) fiber by microbe was studied.The degree of DTP degradation was determined by High Performance Liquid Chromatography (HPLC) to be more than 90%.The products after degradation of DTP and PET fiber were various.The degradation of DTP can be described by the first-order reaction model.The degradation of PET fiber was found to be little,but surface erosion of PET fiber could be clearly seen from the SEM photographs indicating there occurred some traces of biodegradation on the PET fiber surface.