Thermophilic and thermotolerant bacteria that assimilate methane]

Microorganisms assimilating methane at temperatures above 40 degrees C were isolated from various natural sources: ooze, mud, waste water of coal pits. The bacteria are obligate methylotrophs and are represented by two groups: (a) thermotolerant, growing at 37 to 45 degrees C; and (b) thermophilic, growing at 50 to 62 degrees C. The selective factor used to isolate various physiological forms of methylotrophs is corresponding temperatures of growth which allow to isolate from the same substrate meso-, thermotolerant, and thermophilic forms. Morphological and physiological properties of the strains are described. The thermotolerant cultures of methylotrophs are similar to Methylobacter vinelandii, though differ from it by some characteristics. The thermophilic microorganisms should be classed as a separate species Methylococcus thermophilus.     

The genome of lipid-containing bacteriophage PRD1, which infects gram-negative bacteria, contains long, inverted terminal repeats.

The bacteriophage PRD1 is a lipid-bearing phage that infects a wide variety of gram-negative bacteria, including Escherichia coli and Salmonella typhimurium when they contain the appropriate plasmid. It contains a linear duplex DNA molecule that is covalently bound by its 5' ends to a terminal protein. We report here that the PRD1 genome contains a 111-base-pair terminal inverted repeat which does not bear homology to that of any known linear duplex DNAs with terminal proteins. We further report that its 3' termini are susceptible to enzymatic digestion by exonuclease III.     

混合菌处理高浓度泔脚原液的研究

泔脚水含有大量的淀粉、蛋白质和动植物油,这些物质极易发生腐烂变质,对周围环境和水体造成严重污染。本实验采用由筛选到的微生物构成的活性污泥—活性炭混合法对高浓度泔脚原液不经稀释,直接进行处理。实验结果证明,泔脚水中的CODcr、TN和油脂得到明显的去除,水体的透光度得到很大提高。本法操作简单,对设备要求低,非常适合餐饮点分散、泔脚水排放量少的各餐饮单位采用。根据对α-淀粉酶活力的测定得知,利用CaCO3调节曝气液的pH值,能够提高和稳定α-淀粉酶的活力。     

Enhanced biological treatment of saline wastewater by using halophilic bacteria

Biological treatment of saline wastewater by conventional activated sludge culture usually results in low removal of chemical oxygen demand (COD) because of plasmolysis of the organisms at high salt concentrations. Since salt removal operations by physicochemical processes before biological treatment are costly, a salt-tolerant organism (Halobacter halobium) was used for effective biological treatment of saline wastewater in this study. Halobacter halobium was used in activated sludge culture for COD removal from saline wastewater (1–5% salt) by fed-batch operation of an aeration tank. Inclusion of Halobacter halobium into activated sludge culture improved the rate and extent of COD removals especially with salt above 2% (w/v).     

Ether-containing lipids of methanogenic bacteria

Acid-hydrolysis of the phospholipid fraction of $\text{Methanobacterium thermoautotrophicum}\text{,}\text{Methanobacterium formicicum}$ and $\text{Methanospirillum hungatii}$ demonstrated the presence of two neutral lipid products. Characterization of these lipids resulted in their identification as dialkyl glyceryl ether and diglycerol tetraethers. The ether-linked alkyl chains were identified as the 20- and 40-carbon branched chains for the diether and tetraether, respectively. $\text{M}\text{.}\text{thermoautotrophicum}$ and $\text{M}\text{.}\text{formicicum}$ were also characterized by the presence of acid-stable phospholipid components.     

Treatment of municipal wastewater using laterite-based constructed soil filter

The present study reports the performance of municipal wastewater treatment plant located at Mumbai, India using laterite soil-based constructed soil filter (CSF) system monitored over 17 months. The results indicated increase in dissolved oxygen levels and reduction of chemical oxygen demand (COD) from 135.4 ± 79.4 to 28.8 ± 19.5 mg/L with first order rate constant (K_d) of 0.23 h^?1. The bio-chemical oxygen demand (BOD) reduced from 92 to less than 10 mg/L with K_d of 0.35 h^?1; suspended solids reduction from mean 188 to 12–18 mg/L and turbidity reduction from mean 140 to 5.0 ± 3.4 NTU. The seasonal data showed 3.2 ± 0.9, 2.8 ± 0.4 and 2.85 ± 1.0 log order removal for total coliform, fecal coliform and heterotrophic plate count, respectively. The unique features of the system include a single unit, low HRT, high hydraulic loading, no chemicals, pretreatment and mechanical aeration, odor free, low energy requirement (0.04 kWh/m³), and green ambience.     

Treatment of saline municipal wastewater using hybrid growth system

Background

In this study, a hybrid treatment system (Fluidized Bed positioned in a biological reactor of an Activated Sludge process) was used to treat saline domestic wastewater. The performance of the mentioned hybrid system was compared with the conventional activated sludge. A pilot study was conducted, and Chemical Oxygen Demand (COD), Electrical Conductivity (EC), Total Dissolved Solids (TDS) and pH were measured to investigate treatment efficiency. Three saline wastewater samples with salt concentrations of 0.5, 1, and 1.5 % and detention times of 2, 4 and 6 h were loaded into both rectors of hybrid system and activated sludge.

Results

The results showed that Chemical Oxygen Demand (COD) removals at salt concentrations of 0.5, 1, 1.5 % were equal to 80, 71, 48.5 for the hybrid system and 62, 47.7, 26.5 for the activated sludge system respectively. Likewise, similar results obtained for other contamination indices indicating the superiority of the hybrid system in comparison to activated sludge system. Moreover, another advantage of the hybrid system was that the activated sludge needed sludge returning while sludge returning was not required in the hybrid system. In addition, by loading fixed rate of air into both systems, dissolved oxygen concentration in the hybrid reactor is higher than the conventional reactor.

Conclusions

Therefore, the hybrid system had a significantly higher efficiency than conventional reactor to treat saline domestic wastewater.

     

Structural proteins of a lipid-containing bacteriophage which replicates in Escherichia coli: phage PR4.

PR4 is a lipid-containing bacteriophage which is able to replicate in Escherichia coli. The virus was labeled with either [14C]leucine and [14C]threonine or H235SO4 and then purified by several rounds of sucrose gradient centrifugation. Autoradiographs showed the virus to be composed of six major protein species with molecular weights (1) 68 000, (2) 47 500, (3) 38 500, (4) 35 000, (5) 20 700, (6) 16 500 daltons. Electropherograms showed protein No. 2 to be the major protein, comprising about 43% of the total weight of viral protein.     

Marine bacteria which produce tetrodotoxin

A number of type strains of marine bacteria, including members of the family Vibrionaceae, were cultured and examined for tetrodotoxin productivity by high-performance liquid chromatography and gas chromatography-mass spectrometry. Most of the Vibrionaceae strains produced tetrodotoxin, anhydrotetrodotoxin, or both.     

Behavior of lipids in biological wastewater treatment processes

Lipids (characterized as oils, greases, fats and long-chain fatty acids) are important organic components of wastewater. Their amount, for example, in municipal wastewater is approximately 30–40% of the total chemical oxygen demand. The concern over the behavior of lipids in biological treatment systems has led to many studies, which have evaluated their removal, but still the exact behavior of lipids in these processes is not well understood. In this review, we discuss the current knowledge of how lipids/fatty acids affect both aerobic and anaerobic processes and specific methods that have been used in an attempt to enhance their removal from wastewater. Overall, the literature shows that lipids/fatty acids are readily removed by biological treatment methods, inhibitory to microbial growth as well as the cause of foaming, growth of filamentous bacteria and floc flotation.     

Phosphate removal from the returned liquor of municipal wastewater treatment plant using iron-reducing bacteria

AIM: The application of iron-reducing bacteria (IRB) to phosphate removal from returned liquor (liquid fraction after activated sludge digestion and anaerobic sludge dewatering) of municipal wastewater treatment plant (WWTP) was studied. METHODS AND RESULTS: An enrichment culture and two pure cultures of IRB, Stenotrophomonas maltophilia BK and Brachymonas denitrificans MK identified by 16S rRNA gene sequencing, were produced using returned liquor from a municipal WWTP as carbon and energy source, and iron hydroxide as oxidant. The final concentration of phosphate increased from 70 to 90 mg l(-1) in the control and decreased from 70 to 1 mg l(-1) in the experiment. The mass ratio of removed P to produced Fe(II) was 0.17 g P g(-1) Fe(II). The strain S. maltophilia BK showed the ability to reduce Fe(III) using such xenobiotics as diphenylamine, m-cresol, 2,4-dichlorphenol and p-phenylphenol as sole sources of carbon under anaerobic conditions. CONCLUSIONS: Bacterial reduction of ferric hydroxide enhanced the phosphate removal from the returned liquor. SIGNIFICANCE AND IMPACT OF THE STUDY: The ability of the facultative anaerobes S. maltophilia BK and B. denitrificans MK to reduce Fe(III) was shown. These micro-organisms can be used for anaerobic removal of phosphate and xenobiotics by bacterial reduction of ferric ions.     

Detection of polyhydroxyalkanoate-accumulating bacteria from domestic wastewater treatment plant using highly sensitive PCR primers

Polyhydroxyalkanoate (PHA) is a class of biodegradable plastics that have great potential applications in the near future. In this study, the micro-biodiversity and productivity of PHA-accumulating bacteria in activated sludge from a domestic wastewater treatment plant were investigated. A previously reported primer set and a selfdesigned primer set (phaCF1BO/phaCR2BO) were both used to amplify the PHA synthase (phaC) gene of isolated colonies. The new primers demonstrated higher sensitivity for phaC, and combining the PCR results of the two primer sets was able to widen the range of detected genera and raise the sensitivity to nearly 90%. Results showed that 85.3% of the identified bacteria were Gram-negative, with Ralstonia as the dominant genus, and 14.7% were Gram-positive. In addition, Zoogloea and Rhizobium contained the highest amounts of intracellular PHA. It is apparent that glucose was a better carbon source than pentone or tryptone for promoting PHA production in Micrococcus. Two different classes, class I and class II, of phaC were detected from alphaproteobacteria, betaproteobacteria, and gammaproteobacteria, indicating the wide diversity of PHA-accumulating bacteria in this particular sampling site. Simultaneous wastewater treatment and PHA production is promising by adopting the high PHAaccumulating bacteria isolated from activated sludge.     

新型固定化硝化细菌和好氧反硝化细菌处理氨氮废水

以改性沸石、聚乙烯醇、海藻酸钠作为固定化载体材料,硼酸和氯化钙作为交联剂,采用吸附-包埋-交联法将硝化细菌和好氧反硝化细菌复合固定化制备成微生物小球.通过复合菌配比实验,考察其对氨氮的去除率以及亚硝酸盐和硝酸盐的累积量;对制成的固定化小球做四因素三水平的正交实验,考察不同条件下对氨氮的去除率.结果表明,硝化细菌和好氧反硝化细菌配比为3:2时,氨氮去除率最高达82.32%,亚硝酸盐和硝酸盐的累积量为0.032mg·L^-1和0.053 mg·L^-1;通过正交实验,确定沸石投加量为2g·100mL^-1、温度为30℃、pH值为7.5、振荡速度为130r·min^-1时,对氨氮达到最好的去除效果,去除率达90.31%,此法制得的小球机械性能和吸水性能良好.     

Marine bacteria which produce tetrodotoxin.

A number of type strains of marine bacteria, including members of the family Vibrionaceae, were cultured and examined for tetrodotoxin productivity by high-performance liquid chromatography and gas chromatography-mass spectrometry. Most of the Vibrionaceae strains produced tetrodotoxin, anhydrotetrodotoxin, or both.     

Treatment of distillery wastewater discharged from beet molasses-spirits production using yeast

Treatment of wastewater discharged from beet molasses-spirits production using yeast was studied. Two flocculant strains, Hansenula fabianii J 640-4-1 and Hansenula anomala J 45-N-5, and a strain, I-44, isolated from soil were suitable for treatment of wastewater at the concentration of 47,300 ppm of total organic carbon (TOC). Especially in the case of 2-step treatment using J 45-N-5 and I-44, TOC decreased to 11,900 ppm, and the C/N ratio (TOC/Total nitrogen) decreased from 14.8 to 4.6.     

Treatment of dairy wastewater using constructed wetlands and intermittent sand filters

In Ireland, the most common method of disposal of dairy parlour washings is by land spreading. This treatment method has numerous problems, namely high-labour requirements and the potential for eutrophication of surface and ground waters. Constructed wetlands are commonly used for treatment of secondary municipal wastewaters and they have been gaining popularity for treatment of agricultural wastewaters in Ireland. Intermittent sand filtration may offer an alternative to traditional treatment methods. As well as providing comparable treatment performance, they also have a smaller footprint, due to the substantially higher organic loading rates that may be applied to their surfaces. This paper discusses the performance and design criteria of constructed wetlands for the treatment of domestic and agricultural wastewater, and sand filters for the treatment of domestic wastewater. It also proposes sand filtration as an alternative treatment mechanism for agricultural wastewater and suggests design guidelines.     

Topology and transport of membrane lipids in bacteria

The last two decades have witnessed a break-through in identifying and understanding the functions of both the proteins and lipids of bacterial membranes. This development was parallelled by increasing insights into the biogenesis, topology, transport and sorting of membrane proteins. However, progress in research on the membrane distribution and transport of lipids in bacteria has been slow in that period. The development of novel biochemical in vitro approaches and recent genetic studies have increased our understanding of these subjects. The aim of this review is to present an overview of the current knowledge of the distribution and transport of lipids in both Gram-positive and Gram-negative bacteria. Special attention is paid to recently obtained results, which are expected to inspire further research to finally unravel these poorly understood phenomena.     

The lipids of phosphorescent Vibrio albensis bacteria]

The lipid composition of fluorescent vibrios, V. eltor and nonagglutinating vibrios has been studied. In the fraction of polar lipids phosphatidylethanolamine, phosphatidylinositol and cardiolipin and in the fraction of neutral lipids monoglycerides, free fatty acids, diglycerides, triglycerides, sterol esters have been identified. The fatty acid composition of some classes of neutral lipids have been determined. Both similarity and differences between the strains under study in their lipid and fatty acid composition have been established.