浸矿细菌-钩端螺旋菌属菌株研究进展

钩端螺旋菌属菌株在微生物浸矿工业中具有重要作用。介绍了钩端螺旋菌属菌株的种类、特性,分离、培养方法,以及近些年来有关该属菌株在分子生物学及浸矿机理方面的研究进展。     

剩余活性污泥完全资源化利用微生物集成技术

剩余活性污泥完全资源化利用微生物集成技术包括: 使用土著PHA合成菌回注法驯化并发酵活性污泥, 生产生物降解材料聚羟基脂肪酸酯(PHA); 采用土著嗜酸性氧化亚铁硫杆菌和氧化硫硫杆菌进行生物淋滤, 去除重金属; 以解磷菌和解钾菌为菌种, 进行固态发酵, 生产生物菌肥。结果表明, 500 L中试PHA占挥发性悬浮固体的20%以上; 重金属含量达到国家排放要求; 生物菌肥中活菌数大于1×108 个/g以上。实现了剩余活性污泥的近零排放。     

Bioleaching of heavy metals from contaminated soil using <Emphasis Type="Italic">Acidithiobacillus thiooxidans</Emphasis>: effect of sulfur/soil ratio

Bioleaching of heavy metals from contaminated soil was carried out using indigenous sulfur oxidizing bacterium Acidithiobacillus thiooxidans. Experiments were carried out by varying sulfur/soil ratio from 0.03 to 0.33 to evaluate the optimum ratio for efficient bioleaching of heavy metals from soil. The influence of sulfur/soil ratio on the bioleaching efficiency was assessed based on decrease in pH, increase in oxidation–reduction potential, sulfate production and solubilization of heavy metals from the soil. Decrease in pH, increase in oxidation–reduction potential and sulfate production was found to be better with the increase in sulfur/soil ratio. While the final pH of the system with different sulfur/soil ratio was in the range of 4.1–0.7, oxidation reduction potential varied from 230 to 629 mV; sulfate production was in the range of 2,786–8,872 mg/l. Solubilization of chromium, zinc, copper, lead and cadmium from the contaminated soil was in the range of 11–99%. Findings of the study will help to optimize the ratio of sulfur/soil to achieve effective bioleaching of heavy metals from contaminated soils.     

浸矿细菌—钩端螺旋菌属菌株研究进展*

钩端螺旋菌属菌株在微生物浸矿工业中具有重要作用。介绍了钩端螺旋菌属菌株的种类、特性,分离、培养方法,以及近些年来有关该属菌株在分子生物学及浸矿机理方面的研究进展。     

雄黄的生物浸出

<正>雄黄(Realgar,As4S4)是一种含砷的硫化物,作为一种中药砷剂已有上千年的历史。近年来,雄黄治疗血液系统疾病、恶性淋巴系统疾病取得了明显的疗效,引起人们广泛的关注[1]。雄黄的传统制备方法包括酸提、煅烧、膜分离,以及机械研磨等[2-3],然而这些方法炮制的雄黄水溶性低、胃肠道吸收差、毒性高以及生物利用度低的缺点严重限制了它的临床应用[4]。生物浸出(Bioleaching)是一种从低品位矿物中提取金属     

高矿浆浓度下黄铜矿浸出过程中微生物群落结构变化规律

目的：为阐明微生物群落演替及功能与浸出效率之间关系奠定基础,以及如何提高黄铜矿生物浸出效率和铜回收率提供理 论依据。方法：通过连续传代培养进行驯化,使得复合菌群的矿浆浓度耐受能力达到25 %（w/v）。采用该复合菌群在25 %矿浆浓 度下浸出黄铜矿,同时利用变性梯度凝胶电泳和克隆文库技术分析浸出过程中的微生物多样性。最后,采用实时荧光定量PCR 对 浸出过程中微生物群落结构进行定量解析。结果：28天内黄铜矿浸出率能够达到95.1 %,而驯化前的浸出率只有51.5%。该复合 菌群主要由Acidithiobacillus caldus, Sulfobacillus acidophilus,和Fereoplasma theroplasma thermophilum组成,其中Acidithbacillus caldus是浸出前期和后期的优势种群,而Sulfobacillus acidophilus在浸出中期均有竞争优势, Ferroplasma thermophilum在整个浸出过程中占 据整个群落的比例均较低。结论：本研究获得的复合菌群具有较强的浸出黄铜矿能力, Acidithiobacillus caldus和Sulfobacillus acidophilus在浸出过程中起着重要的作用,pH 值和铜浸出率与群落结构相关性较高。     

Novel bacterial sulfur oxygenase reductases from bioreactors treating gold-bearing concentrates

The microbial community and sulfur oxygenase reductases of metagenomic DNA from bioreactors treating gold-bearing concentrates were studied by 16S rRNA library, real-time polymerase chain reaction (RT-PCR), conventional cultivation, and molecular cloning. Results indicated that major bacterial species were belonging to the genera Acidithiobacillus, Leptospirillum, Sulfobacillus, and Sphingomonas, accounting for 6.3, 66.7, 18.8, and 8.3%, respectively; the sole archaeal species was Ferroplasma sp. (100%). Quantitative RT-PCR revealed that the 16S rRNA gene copy numbers (per gram of concentrates) of bacteria and archaea were 4.59 × 10⁹ and 6.68 × 10⁵, respectively. Bacterial strains representing Acidithiobacillus, Leptospirillum, and Sulfobacillus were isolated from the bioreactors. To study sulfur oxidation in the reactors, pairs of new PCR primers were designed for the detection of sulfur oxygenase reductase (SOR) genes. Three sor-like genes, namely, sor _Fx, sor _SA, and sor _SB were identified from metagenomic DNAs of the bioreactors. The sor _Fx is an inactivated SOR gene and is identical to the pseudo-SOR gene of Ferroplasma acidarmanus. The sor _SA and sor _SB showed no significant identity to any genes in GenBank databases. The sor _SB was cloned and expressed in Escherichia coli, and SOR activity was determined. Quantitative RT-PCR determination of the gene densities of sor _SA and sor _SB were 1,000 times higher than archaeal 16S rRNA gene copy numbers, indicating that these genes were mostly impossible from archaea. Furthermore, with primers specific to the sor _SB gene, this gene was PCR-amplified from the newly isolated Acidithiobacillus sp. strain SM-1. So far as we know, this is the first time to determine SOR activity originating from bacteria and to document SOR gene in bioleaching reactors and Acidithiobacillus species.     

Manganese biomining: A review

Biomining comprises of processing and extraction of metal from their ores and concentrates using microbial techniques. Currently this is used by the mining industry to extract copper, uranium and gold from low grade ores but not for low grade manganese ore in industrial scale. The study of microbial genomes, metabolites and regulatory pathways provide novel insights to the metabolism of bioleaching microorganisms and their synergistic action during bioleaching operations. This will promote understanding of the universal regulatory responses that the biomining microbial community uses to adapt to their changing environment leading to high metal recovery. Possibility exists of findings ways to imitate the entire process during industrial manganese biomining endeavor. This paper reviews the current status of manganese biomining research operations around the world, identifies factors that drive the selection of biomining as a processing technology, describes challenges in exploiting these innovations, and concludes with a discussion of Mn biomining’s future.     

Chemical constituents and antibacterial activity of the leaf essential oil of <Emphasis Type="Italic">Feronia limonia</Emphasis>

Bioleaching of uranium was carried out with Turamdih ore sample procured from Uranium Corporation of India Limited, Jaduguda. The bacterial strain that was used in the leaching experiments was isolated from the Jaduguda mine water sample. Efficiency of bioleaching was studied by varying parameters like pulp density and initial ferrous concentration as source of energy. It is observed that the efficiency of bioleaching was 49% at 10% pulp density (w/v) and initial pH 2.0. Addition of external has no effect on efficiency of bioleaching showing domination of direct leaching mechanism over indirect.     

Copper removal from an industrial waste by bioleaching

Summary Copper contained in a solid industrial waste produced in a silicone manufacturing process was leached with spent iron medium from aThiobacillus ferrooxidans culture. Most effective leaching was observed in a continuously fed, dual reactor system. Spent iron medium was generated by growingT. ferrooxidans in 0.9 K iron medium at pH 1.5 in the first reactor, and was transferred to a second reactor in which it leached the copper from the waste. Leaching was effective at a pulp density of the waste material as high as 20%. In experiments run at a pulp density of 2.5%, the spent iron medium was most efficient in leaching copper when it was first diluted 100-fold with a mineral salts solution at pH 1.5. Removal of the copper from the waste appeared to involve its displacement by acid, dissolved mineral salts, and ferric iron. Potentials for practical application of this process are discussed.