Bacterial community analysis in upflow multilayer anaerobic reactor treating high‐solids organic wastes

A novel anaerobic digestion configuration, the upflow multi‐layer anaerobic reactor (UMAR), was developed to treat high‐solids organic wastes. The UMAR was hypothesized to form multi‐layer along depth due to the upflow plug flow; use of a recirculation system and a rotating distributor and baffles aimed to assist treating high‐solids influent. The chemical oxygen demand (COD) removal efficiency and methane (CH₄) production rate were 89% and 2.10 L CH₄/L/d, respectively, at the peak influent COD concentration (110.4 g/L) and organic loading rate (7.5 g COD/L/d). The 454 pyrosequencing results clearly indicated heterogeneous distribution of bacterial communities at different vertical locations (upper, middle, and bottom) of the UMAR. Firmicutes was the dominant (>70%) phylum at the middle and bottom parts, while Deltaproteobacteria and Chloroflexi were only found in the upper part. Potential functions of the bacteria were discussed to speculate on their roles in the anaerobic performance of the UMAR system. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:1226–1234, 2017     

烟草生产废弃物提取烟碱的研究

从烟草生产废弃物中提取的烟碱是重要的医药和化工原料,本研究分析了不同烟草类型的废弃物烟碱含量,论述了烟碱在医药、农药和卷烟添加剂方面的用途,作为废物利用,开发天然产物具有十分重要的经济价值。     

Aquatic vegetation and trophic condition of Cape Cod (Massachusetts,U.S.A.) kettle ponds

The species composition and relative abundance of aquatic macrophytes was evaluated in five Cape Cod, Massachusetts, freshwater kettle ponds, representing a range of trophic conditions from oligotrophic to eutrophic. At each pond, aquatic vegetation and environmental variables (slope, water depth, sediment bulk density, sediment grain size, sediment organic content and porewater inorganic nutrients) were measured along five transects extending perpendicular to the shoreline from the upland border into the pond. Based on a variety of multivariate methods, including Detrended Correspondence Analysis (DCA), an indirect gradient analysis technique, and Canonical Correspondence Analysis (CCA), a direct gradient approach, it was determined that the eutrophic Herring Pond was dominated by floating aquatic vegetation (Brasenia schreberi, Nymphoides cordata, Nymphaea odorata), and the algal stonewort, Nitella. Partial CCA suggested that high porewater PO₄-P concentrations and fine-grained sediments strongly influenced the vegetation of this eutrophic pond. In contrast, vegetation of the oligotrophic Duck Pond was sparse, contained no floating aquatics, and was dominated by emergent plants. Low porewater nutrients, low sediment organic content, high water clarity and low pH (4.8) best defined the environmental characteristics of this oligotrophic pond. Gull Pond, with inorganic nitrogen-enriched sediments, also exhibited a flora quite different from the oligotrophic Duck Pond. The species composition and relative abundance of aquatic macrophytes provide good indicators of the trophic status of freshwater ponds and should be incorporated into long-term monitoring programs aimed at detecting responses to anthropogenically-derived nutrient loading.     

Comparison of Rhizopus nigricans in a pelleted growth form with some other types of waste microbial biomass as biosorbents for metal ions

Biosorption of metal ions (Li⁺, Ag⁺, Pb²⁺, Cd²⁺, Ni²⁺, Zn²⁺, Cu²⁺, Sr²⁺, Fe²⁺, Fe³⁺ and Al³⁺) by Rhizopus nigricans biomass was studied. It was shown that metal uptake is a rapid and pH-dependent process, which ameliorates with increasing initial pH and metal concentrations. Different adsorption models: Langmuir, Freundlich, split-Langmuir and combined nonspecific-Langmuir adsorption isotherm were applied to correlate the equilibrium data. The maximum biosorption capacities for the individual metal ions were in the range from 160 to 460 mol/g dry weight. Scatchard transformation of equilibrium data revealed diverse natures of biomass metal-binding sites. The binding of metals was also discussed in terms of the hard and soft acids and bases principle. The maximum biosorption capacities and the binding constant of R. nigricans were positively correlated with the covalent index of metal ions.The following types of waste microbial biomass originating as by-products from industrial bioprocesses were tested for biosorption of metal ions: Aspergillus terreus, Saccharomyces cerevisiae, Phanerochaete chrysosporium, Micromonospora purpurea, M. inyoensis and Streptomyces clavuligerus. The determined maximum biosorption capacities were in the range from 100 to 500 mol/g dry weight. The biosorption equilibrium was also represented with Langmuir and Freundlich sorption isotherms.     

In situ versus laboratory estimations of length–weight regression and growth rate of Daphnia magna (Branchiopoda, Anomopoda) from an aerated waste stabilization pond

The present paper questions the adequacy of using length–weight regressions and growth rates calculated in the laboratory under constant physico-chemical and food conditions for the estimation of biomass and secondary production of animals living in a variable environment from the physico-chemistry and food availability point of view. Length–weight regressions (LWR) and growth rate of Daphnia magna were determined in situat five key periods of the year. In parallel, LWR and growth rate were determined in laboratory incubators at temperature adjusted to the mean temperature measured during the in situexperiments. LWR estimated from pond daphnids collected during the in situ experiments were, on the whole, not significantly different from LWR established during laboratory experiments, indicating that the food availability was globally similar in the laboratory and in situexperiments, even though food items were substantially different between the experiments. In situ algal biomass was indeed low compared to the algal biomass in laboratory experiments, but high biomasses of bacteria, protozoa and detritus were available for daphnid feeding in the tubes incubated in situ. Growth rate of D. magnawas monitored in situusing 50-ml tubes closed with Nylon net (mesh size = 80 m) and in the laboratory using 50-ml glass flasks. The physico-chemical, bacteriological and algological variables were checked to be similar in the tubes and in the pond. Growth rates varied according to the size of the animal and according to the water temperature. The maximum growth rates were observed for juveniles at 20.2 °C. Growth rates were also determined in the laboratory at temperature corresponding to the mean temperature recorded in the pond during the in situ growth experiments. Differences between in situ and laboratory body length–growth rate regressions (LgR) were observed for the experiments conducted at 15.6 °C and 23.6 °C. Due to differences in LWR and LgR between in situ and laboratory experiments, biomass and daily production estimated from laboratory cultures were found to be significantly, but not severely, higher than biomass and daily production estimated on the basis of in situ experiments. It has been, therefore, concluded that, when the constraints linked to the realization of in situ growth experiments are too strong, the laboratory approach is fully justified.     

The effect of chronic cortisol elevation on urea metabolism and excretion in the rainbow trout (<Emphasis Type="Italic">Oncorhynchus mykiss</Emphasis>)

The objective of this study was to investigate the possible involvement of cortisol in controlling urea metabolism and excretion in the ammoniotelic rainbow trout (Oncorhynchus mykiss). Trout fitted with dorsal aortic and internal urinary catheters received either no implant (control), or were implanted with coconut oil (sham), cortisol in coconut oil, RU486, a glucocorticoid receptor blocker, in coconut oil, or cortisol+RU486 in coconut oil, and monitored over 72 h. Rainbow trout treated with cortisol (±RU486) had similarly elevated plasma cortisol concentrations that were six fold greater than in control and sham fish. Elevated circulating cortisol concentrations caused a three-fold rise in plasma and urine urea concentrations, which was blocked by RU486. Similarly, a positive correlation between plasma cortisol and plasma urea concentrations was observed in fish treated with cortisol alone but not in fish treated with cortisol+RU486. Cortisol treatment caused an elevation in branchial (two fold higher) and urinary (three fold higher) excretion rates of urea compared to sham-implanted fish, which was prevented by treatment with RU486. However, as branchial and renal clearance were unaffected, there appears to be no stimulation or inhibition of urea excretion mechanisms in the gill or kidney separate from effects due to changes in plasma urea concentrations. Thus, cortisol and glucocorticoid receptors appear to be involved in the regulation of endogenous urea production but not in the control of urea excretory mechanisms in the ammoniotelic trout.Abbreviations GFR glomerular filtration rate - GS glutamine synthetase - O-UC ornithine urea cycle - PEG polyethylene glycol - UFR urine flow rate Communicated by: G. Heldmaier     

The effects of the Penicillium mycotoxins citrinin, cyclopiazonic acid, ochratoxin A, patulin, penicillic acid, and roquefortine C on in vitro proliferation of porcine lymphocytes

The in vitro effect of each of the Penicillium mycotoxins citrinin (CIT), cyclopiazonic acid (CPA), ochratoxin A (OTA), patulin (PAT), penicillic acid (PIA) and roquefortine C (RQC) on mitogen induced lymphocyte proliferation was determined using purified lymphocytes from 6 piglets. Dose response curves for each mycotoxin were generated and the concentrations producing 50% inhibition of cell proliferation (IC₅₀) were estimated. OTA and PAT were the most potent toxins with IC₅₀ of 1.3 and 1.2 μmol/l, respectively (0.52 and 0.18 mg/l, respectively). Based on molar concentrations, OTA was 15, 30, 40, and 65 times more potent as an inhibitor than PIA, CIT, CPA and RQC, respectively.     

Comparative life cycle assessment of two landfill technologies for the treatment of municipal solid waste

Goal and Scope  The potential environmental impacts associated with two landfill technologies for the treatment of municipal solid waste (MSW), the engineered landfill and the bioreactor landfill, were assessed using the life cycle assessment (LCA) tool. The system boundaries were expanded to include an external energy production function since the landfill gas collected from the bioreactor landfill can be energetically valorized into either electricity or heat; the functional unit was then defined as the stabilization of 600 000 tonnes of MSW and the production of 2.56x10⁸ MJ of electricity and 7.81x10⁸ MJ of heat. Methods  Only the life cycle stages that presented differences between the two compared options were considered in the study. The four life cycle stages considered in the study cover the landfill cell construction, the daily and closure operations, the leachate and landfill gas associated emissions and the external energy production. The temporal boundary corresponded to the stabilization of the waste and was represented by the time to produce 95% of the calculated landfill gas volume. The potential impacts were evaluated using the EDIP97 method, stopping after the characterization step. Results and Discussion  The inventory phase of the LCA showed that the engineered landfill uses 26% more natural resources and generates 81% more solid wastes throughout its life cycle than the bioreactor landfill. The evaluated impacts, essentially associated with the external energy production and the landfill gas related emissions, are on average 91% higher for the engineered landfill, since for this option 1) no energy is recovered from the landfill gas and 2) more landfill gas is released untreated after the end of the post-closure monitoring period. The valorization of the landfill gas to electricity or heat showed similar environmental profiles (1% more raw materials and 7% more solid waste for the heat option but 13% more impacts for the electricity option). Conclusion and Recommendations  The methodological choices made during this study, e.g. simplification of the systems by the exclusion of the identical life cycle stages, limit the use of the results to the comparison of the two considered options. The validity of this comparison could however be improved if the systems were placed in the larger context of municipal solid waste management and include activities such as recycling, composting and incineration.     

Physicochemical characterization and antimicrobial properties of rhamnolipids produced by Pseudomonas aeruginosa 47T2 NCBIM 40044

Pseudomonas aeruginosa 47T2, grown in submerged culture with waste frying oil as a carbon source, produced a mixture of rhamnolipids with surface activity. Up to 11 rhamnolipid homologs (Rha-Rha-C(8)-C(10); Rha-C(10)-C(8)/Rha-C(8)-C(10);Rha-Rha-C(8)-C(12:1); Rha-Rha-C(10)-C(10); Rha-Rha-C(10)-C(12:1); Rha-C(10)-C(10); Rha-Rha-C(10)-C(12)/Rha-Rha-C(12)-C(10); Rha-C(10)-C(12:1)/Rha-C(12:1)-C(10); Rha-Rha-C(12:1)-C(12); Rha-Rha-C(10)-C(14:1); Rha-C(10)-C(12)/Rha-C(12)-C(10)) were isolated from cultures of P. aeruginosa 47T2 from waste frying oil and identified by HPLC-MS analysis. This article deals with the production, isolation, and chemical characterization of the rhamnolipid mixture RL(47T2). The physicochemical and biological properties of RL(47T2) as a new product were also studied. Its surface tension decreased to 32.8 mN/m; and the interfacial tension against kerosene to 1 mN/m. The critical micellar concentration for RL(47T2) was 108.8 mg/mL. The product showed excellent antimicrobial properties. Antimicrobial activity was evaluated according to the minimum inhibitory concentration (MIC), the lowest concentration of an antimicrobial agent that inhibits development of visible microbial growth. Low MIC values were found for bacteria Serratia marcescens (4 microg/mL), Enterobacter aerogenes (8 microg/mL), Klebsiella pneumoniae (0.5 microg/mL), Staphylococcus aureus and Staphylococcus epidermidis (32 microg/mL), Bacillus subtilis (16 microg/mL), and phytopathogenic fungal species: Chaetonium globosum (64 microg/mL), Penicillium funiculosum (16 microg/mL), Gliocadium virens (32 microg/mL) and Fusarium solani (75 microg/mL).     

Linkage identity is a major factor in determining the effect of PEG-ylated surfactants on permeability of phosphatidylcholine liposomes

The permeability effects induced by single-chained and double-chained poly(ethylene glycol)-surfactants were investigated by measuring the leakage of the fluorescent dye 5(6)-carboxy fluorescein from EPC liposomes. The standard incorporated amount of the surfactants was 5 mol%. Depending on the size of the poly(ethylene glycol) chain and especially on the type of linkage between the polymer and the hydrophobic moiety different leakage profiles were obtained. The presence of a long PEG-polymer resulted in a slower leakage compared with a short analogue. More importantly, the linkage identity was decisive for whether an overall reduction or increase in permeability was obtained. When the hydrocarbon chains were attached to the PEG chain via an ether or an ester the leakage increased compared to pure EPC liposomes. In contrast, if the link was an amide, the leakage was significantly reduced. This effect is assumed to originate from headgroup-headgroup interactions, and most probably hydrogen bonding, between amide and phosphate groups of the PEG-surfactant and the EPC, respectively.