嗜硫性磁性微球技术特异性分离人免疫球蛋白G

利用微悬浮聚合技术,以二乙烯基苯、醋酸乙烯酯为单体,制备了微米级的顺磁性的聚合物微球,磁含量高于24%,饱和磁强度为16.7emu/g,平均粒径介于0.6~20μm,并在其表面修饰二乙烯基砜和2-巯基苯并噻唑。所制备的磁性聚合物微球,在低盐浓度下,依靠配基对抗体的电子-供电子（EDA）效应,可以实现磁性微球对人血清中的免疫球蛋白G（IgG）的特异性吸附行为。在解吸附过程中,洗提液中的盐种类对分离过程产生重要影响。温度对其吸附行为的影响较小,整个分离过程可以在室温条件下进行。利用这种嗜硫性磁球分离技术,条件温和,效率较高,分离出的抗体纯度较高,且生物活性没有损失。

嗜硫类磁性聚合物微球高效分离抗体

用微悬浮聚合技术制备微米级顺磁性的聚合物微球,并通过水解反应在其表面生成丰富的羟基,进而通过二乙烯基砜活化,在其表面修饰2-巯基嘧啶,实现磁性微球对人体免疫球蛋白G(IgG)的特异性识别.进一步探讨了不同解吸附环境,如pH值、温度、离子种类、离子强度等条件,对这种特异性吸附行为的影响.采用此磁性分离技术后,分离抗体的纯度超过92%,抗体活性高于99%.通过连续分离工艺,IgG的分离效率达到86.8%.

Characterization of apparent sulfur oxidation activity of thermophilic archaea in bioleaching of chalcopyrite

The apparent sulfur oxidation activities of four pure thermophilic archaea, Acidianus brierleyi （JCM 8954）, Metallosphaera sedula （YN 23）, Acidianus manzaensis （YN 25） and Sulfolobus metallicus （YN 24） and their mixture in bioleaching chalcopyrite were compared, which were characterized indirectly by the evolution of the cells concentration, pH value and sulfate ions concentration in solution. The results show that the mixed culture contributed significantly to the raising of leaching rate, which suggests that the mixed culture had a higher sulfur oxidation activity than the pure culture. Meanwhile, the results also indicate that the changes of parameters characterizing the sulfur oxidation activity of thermophilic archaea are often influenced by many factors, so it is hard to reflect accurately the specific sulfur oxidation activities among the different sulfur-oxidizing microbes when bioleaching chalcopyrite at different conditions. Accordingly, an efficient method to characterize microbial sulfur oxidation activity appears to be desirable.

Preservation efficiency of new cryoprotectant used for Acidithiobacillus ferrooxidans in liquid nitrogen

The efficiency of a new cryoprotectant,GP,for the preservation of Acidithiobacillus ferrooxidans（A.ferrooxidans） strain DC in liquid nitrogen was investigated.The optimal concentration of this new cryoprotectant for the maximal viable cell recovery and the highest ferrous ion oxidation activity was determined.The results show that 30%（volume fraction） GP is optimal for the cryopreservation with 84.4% of cells surviving,completely oxidizing ferrous ions within 120 h,and growing to a final density of 5.8×107 cell/mL after 6 d in the culture.Furthermore,the optimal residual GP concentration for viable cell recovery after culture of thawed cells in 9K medium for 6 d is 0.6%（volume fraction）.At this concentration,strain DC completely oxidizes ferrous ions within 108 h and grows to a final cell density of 6.8×107 mL-1.Thus,GP is a simple,effective cryoprotectant for the preservation of A.ferrooxidans strain DC in liquid nitrogen.

Isolation and characterization of Acidithiobacillus caldus from several typical environments in China

Six strains of moderately thermophilic sulfur-oxidizing bacteria were isolated from several different typical environments in China. The identities of the isolates were confirmed by analyses of their 16S rRNA genes, and some key physiological traits. The isolates are Gram negative, rod-shaped bacteria, their optimal temperature and pH value for growth are 45-50℃ and 2.5-3.5 respectively. They are autotrophic and used elemental sulfur, sodium thiosulfate and potassium tetrathionate as electron donor, while a little glucose stimulated their growth. 16S rDNA sequences analysis reveals that the strains are phylogenetically clustered to Acidithiobacillus caldus.

Acidophilic bacterial community reflecting pollution level of sulphide mine impacted by acid mine drainage

To reveal the impact of mining on bacterial ecology around mining area,bacterial community and geochemical characteristics about Dabaoshan Mine(Guangdong Province,China)were studied.By amplified ribosomal DNA restriction analysis and phylogenetic analysis,it is found that mining pollution greatly impacts the bacterial ecology and makes the habitat type of polluted environments close to acid mine drainage(AMD)ecology.The polluted environment is acidified so greatly that neutrophil and alkaliphilic microbes are massively dead and decomposed.It provided organic matters that can make Acidiphilium sp.rapidly grow and become the most bacterial species in this niche.Furthermore,Acidithiobacillus ferrooxidans and Leptospirillum sp.are also present in this niche.The amount of Leptospirillum sp.is far more than that of Acidithiobacillus ferrooxidans,which indicates that the concentration of toxic ions is very high.The conclusions of biogeochemical analysis and microbiological monitor are identical. Moreover,because the growth of Acidithiobacillus ferrooxidans and Leptospirillum sp.depends on ferrous iron or inorganic redox sulfur compounds which can be supplied by continual AMD,their presence indicates that AMD still flows into the site.And the area is closer to the outfalls of AMD,their biomasses would be more.So the distinction of their biomasses among different areas can help us to find the effluent route of AMD.

Isolation and characterization of acidophilic bacterium from Dongxiangshan Mine in Xinjiang Province, China

One bioleaching bacterium, named as strain DXS, was isolated from acid mine drainages （AMDs） of Dongxiangshan Mine of Hami, Xinjiang Province, China. The strain DXS is gram-negative and rod-shaped with a size of （0.40±0.05） μm x （1.3±0.5） μm. The optimal temperature and pH for growth are 30 ℃ and pH 2.0, respectively. It can grow autotrophically by using ferrous iron, elemental sulfur and NaS203 as sole energy sources. In the phylogenetic tree, strain DXS has similarity with Acidithiobacillus ferrooxidans type strain ATCC 23270 with 99.57% sequence similarity. The cloning and sequencing of Iro protein gene （iro） and tetrathionate hydrolase gene （tth） reveal that strain DXS is completely identical in iro gene sequence to A. ferrooxidans LY （DQ166841）, and almost identical in tth gene sequene to .4. ferrooxidans （AB259312） （only two nucleotides change）. The bioleaching experiments of marmatite and pyrite reveal that the leached zinc and iron concentrations reach 3.01 g/L and 2.75 g/L, respectively. The strain has a well potential application in industry bioleaching.