Oxygen-limited Environment Research Articles

Production and Characterization of Biochars from Slow Pyrolysis of Different Biomass Materials to Evaluate Properties as Soil Amendments

Biochar, a carbon (C)-rich solid material produced by the thermo-chemical conversion of biomass in an oxygen-limited environment, has been attracting interest due to its potential as a soil amendment. In this study, biomass materials derived from rice (Oryza sativa) straw (RS), rice hull (RH), water hyacinth (Eichhornia crassipes) (WH), and mahogany flower receptacles (Swietenia macrophylla) (MFR) were slowly pyrolyzed under temperatures ranging from 300–650°C using a biochar producing stove. The morphological characteristics and physicochemical properties of biochars were studied using the Brunauer-Emmett-Teller (BET) automated nitrogen multilayer physisorption system, field emission–transmission electron microscopy (FE-TEM), and X-ray energy dispersive spectrometry (EDS). Biochars originating from light materials (RS and WH) showed higher concentrations of essential plant nutrients such as nitrogen (N), phosphorus (P), and potassium (K). The biochar originating from woody MFR had low concentrations of essential plant nutrients. The surface area of the materials was in the 0.473–78.208 m2/g range. The RS and RH biochars demonstrated high surface area with 45.511 and 78.208 m2/g, respectively. The WH biochar showed a low surface area of 9.845 m2/g while the surface area of the MFR biochar was particularly very low at 0.473 m2/g. The high angle annular bright-field (HAABF) images, spectra, and elemental X-ray maps of all the four biochars revealed areas high in carbon, potassium, chlorine, calcium, magnesium, silicon, and aluminum. These biochar properties and mineral agglomerates suggest that biochars can be used as a soil amendment to improve soil fertility.

Physiological response of the giant acorn barnacle, Balanus nubilus, to oxygen-limiting environments

Sessile invertebrates in the nearshore coastal and rocky intertidal habitats can experience oxygen limitation during low tide air exposure and environmental hypoxia events. For some organisms, unique morphological characteristics may make these events especially challenging. The giant acorn barnacle, Balanus nubilus, has the largest muscle fibers in the animal kingdom (diameters can exceed 3 mm in adults). At these extreme sizes, muscle cells may already be at the brink of insufficient oxygen delivery owing to low SA:V ratios and long intracellular diffusion distances. We are interested in characterizing the internal oxygen dynamics of B. nubilus during air exposure and seawater anoxia so that we can better understand how they maintain function of their giant muscle fibers during environmentally-induced oxygen limitation. To this end, we examined the following: 1) hemolymph pO2, pCO2, pH and ion (Na+, Cl−, K+, Ca2+) concentrations across 9 h exposure to air emersion, anoxic immersion and normoxic immersion (control), 2) oxygen consumption rates (MO2) of barnacles held in water and air for 6 h (at 10, 15 and 20 °C), and 3) respiratory behaviors (e.g., % time operculum open or cirri extended, cirral beat frequency) of barnacles during acute (6 h) exposure to emersion, anoxic immersion and normoxic immersion. Our data revealed that hemolymph pO2 declined significantly (by 3 h) in the anoxic barnacles, whereas the air-exposed barnacles maintained hemolymph oxygen levels that were intermediate to the control and anoxia barnacles. We also found that MO2 values for B. nubilus were very similar in seawater and air at a common temperature. These results suggest that B. nubilus can effectively acquire oxygen and support aerobic metabolism while in the air. This assumption was corroborated by our behavioral data, which revealed that air exposed (and anoxic) barnacles spent significantly more time engaged in cirral beating than control barnacles. Such a behavioral preference should enhance oxygen delivery to the internal respiratory surfaces inside the shell. Finally, we found significantly higher hemolymph [K+] in the emersed and anoxic barnacles, which - when coupled to the relatively stable pH values we observed in all treatments - may suggest involvement of K+ ions in an effective acid-base buffering system. In sum, we predict that muscle function would be preserved in B. nubilus during periods of low tide emersion, whereas environmental hypoxia events, which are increasing in frequency and duration as global climates change, have the potential to diminish functionality of their giant muscle fibers.

Activated sludge under free ammonia treatment using gel immobilization technology for long-term partial nitrification with different initial biomass

To achieve stable partial nitrification, activated sludge from a wastewater treatment plant using free ammonia (FA) inhibition was immobilized in a polyvinyl alcohol carrier. After FA treatment at 16.44 mg L−1 for 1 day, due to the increased growth rate gap between ammonium-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB), AOB enrichment and NOB inhibition were achieved within 12 days, with AOB and NOB accounting for 65.61 and 0.05%, respectively. Subsequently, with dissolved oxygen concentrations of 4−5 mg L−1, pH of 7.6–7.8 and temperature of 25 ± 1 °C, the immobilized carrier made of activated sludge achieved more than 90% and more than 86% of nitrite accumulation rate at the influent ammonia concentration of 90−110 mg L−1 and 35−50 mg L−1, respectively. After 50 days operation, the NOB content was 0.10%, indicating the immobilized carrier provided favorable conditions for maintaining the low NOB content. Furthermore, due to the low NOB content in the inoculum and the oxygen-limited environment formed by the increase in the AOB numbers in the carrier, immobilized carrier with different initial biomass (1, 2.5 and 5%) can achieve stable partial nitrification.

Hydrological regulation of Vibrio dynamics in a tropical monsoonal estuary: a classification and regression tree approach.

Dynamics of Vibrio populations in aquatic environments are of concern, as they encompass members pathogenic to humans as well as marine flora and fauna. Spatiotemporal distribution of its culturable abundance for a range of physicochemical and biological parameters in the Cochin estuary (CE), one of the largest tropical monsoonal estuary along the southwest coast of India, witnessed a proliferation of this bacterial group (707 ± 196 CFU ml-1) in downstream stations during a relative dry period. The study for the first time employed classification and regression tree (CART) along with multiple linear regression (MLR) based approaches to explore the nonlinear and linear interactions, respectively, among environmental variables regulating Vibrio abundance in CE. Both the techniques were on consensus to ascertain salinity as the primary determinant of Vibrio dynamics, during the entire sampling period regardless of the seasons, viz., dry and wet. Nevertheless, CART outperformed MLR in performance index, suggesting that in a dynamic system like estuaries, usage of the latter is limited by complex nonlinear relationships among environmental variables. According to CART, Vibrio proliferation observed in downstream stations of the estuary (salinity ≥ 13.4 psu) during a relative dry period was driven by eutrophication (dissolved inorganic phosphate ≥ 1.48 μM L-1) associated with reduced flushing resulting in an oxygen-limited environment (dissolved oxygen < 4.56 ml L-1), wherein phytoplankton production diverts to support microbes. Our results imply that anthropogenic activities and sea level rise in future may prompt Vibrio proliferation, to be a concern for public health and impinge on fisheries yield from tropical estuaries.

Design Features and Performance Evaluation of Natural-Draft, Continuous Operation Gasifier Cookstove

Biomass cookstoves are used as a common source of heating and cooking in developing countries with most improved cookstove design focusing on developing efficiency in thermal conversion of fuels and safer operation than open flame fires. A top-lit-up-draft (TLUD) cookstove utilizes a gasification process similar to pyrolysis where the solid biomass fuels are heated within a oxygen-limited environment and the syngas are burned which reduces carbon content and particulate matter being introduced into the air. The new continuous-operation design is described to have features for: (1) safe addition of solid fuels during combustion of syngas, (2) removal of biochar at the primary air inlet to manage gasification location, and (3) temperature control of the cooksurface through adjustable exhaust paths. The designed cookstove is found to have a diameter to height ratio 0.42-0.47 in order to offer the cleanest burning of the biofuel. The cooking surface is experimentally studied and the thermal gradient is found for compressed wood pellets. Tracking of the coal-bed is studied as a function of time in order to better understand when additional fuel should be added to ensure constant cooking temperature and operation. Numerous exhaust paths explore the cookstove user’s ability to control the temperature contour of the cooksurface.

Effects of biochar on soil fertility and crop productivity in arid regions: a review

Biochar, carbon-rich materials produced during the thermochemical processing of biomass, are receiving increased attention given their potential value as soil amendments. Biochar are formed through pyrolysis processes—heating to several hundred degrees Celsius under oxygen-limited environments—and both the source feedstock and the reaction conditions affect the quality of the resulting chars. Biochar can enhance soil physical and chemical properties and increase agricultural systems’ productivity through direct and indirect effects on crop growth and soil quality. Biochar also may directly help mitigate climate change by sequestering stable carbon compounds in the soil and perhaps indirectly through increased C uptake by trees. As the world faces growing challenges from soil degradation and climate change, biochar application to soils represents a potential pathway forward. Although a large volume of literature exists regarding the use of biochar under favorable climatic conditions, information regarding biochar applications in semiarid and arid climates has been more limited. Evidence of greater water holding capacity and reduced infiltration suggests these materials have potential to improve the productivity of such lands and provides a basis for considering its wider application in the arid environments such as Saudi Arabia. Challenges and limitations for biochar use on a mass scale are also briefly discussed. To move this technology forward, crop and soil scientists should involve economists and agricultural extension educators in studies that consider economic as well as biophysical implications for biochar’s application on a mass scale.

The OxymiR response to oxygen limitation: a comparative microRNA perspective

From squid at the bottom of the ocean to humans at the top of mountains, animals have adapted to diverse oxygen-limited environments. Surviving these challenging conditions requires global metabolic reorganization that is orchestrated, in part, by microRNAs that can rapidly and reversibly target all biological functions. Herein, we review the involvement of microRNAs in natural models of anoxia and hypoxia tolerance, with a focus on the involvement of oxygen-responsive microRNAs (OxymiRs) in coordinating the metabolic rate depression that allows animals to tolerate reduced oxygen levels. We begin by discussing animals that experience acute or chronic periods of oxygen deprivation at the ocean's oxygen minimum zone and go on to consider more elevated environments, up to mountain plateaus over 3500 m above sea level. We highlight the commonalities and differences between OxymiR responses of over 20 diverse animal species, including invertebrates and vertebrates. This is followed by a discussion of the OxymiR adaptations, and maladaptations, present in hypoxic high-altitude environments where animals, including humans, do not enter hypometabolic states in response to hypoxia. Comparing the OxymiR responses of evolutionarily disparate animals from diverse environments allows us to identify species-specific and convergent microRNA responses, such as miR-210 regulation. However, it also sheds light on the lack of a single unified response to oxygen limitation. Characterizing OxymiRs will help us to understand their protective roles and raises the question of whether they can be exploited to alleviate the pathogenesis of ischemic insults and boost recovery. This Review takes a comparative approach to addressing such possibilities.

Influence of pyrolysis temperature and feedstock on the properties of biochars produced from agricultural and industrial wastes

Pyrolysis of waste materials aiming to produce biochar has been considered as an effective strategy to add value and to recycle such materials. The properties of the produced biochars depends on pyrolysis temperature and feedstock type, for example. Some waste materials have been still poorly studied. The objective of this study was to evaluate the changes in physicochemical characteristics, mineral composition, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) of biochars derived from agricultural and industrial wastes produced by different pyrolysis temperatures and feedstocks. Two agricultural solid wastes (poultry litter - PL and swine manure - SM) and three industrial wastes (construction wood - CW, tire - TR and PVC plastic - PVC) were pyrolyzed at five temperatures (300, 400, 500, 600 and 700 °C) in an oxygen-limited environment at a heating rate of 10 °C min−1 for one hour. Increased pyrolysis temperature reduced the yield of solids and volatile compounds and increased pH in water and Ksoluble in all studied biochars. Nevertheless, the temperature caused no significant changes in electrical conductivity, water-soluble nutrients and total elements, and CEC, in the industrial wastes (CW, TR and PVC). The XRD patterns revealed similarities in mineral formation among the studied biochars, including quartz, sylvite, calcite and dolomite. Data of FTIR spectra evidenced the presence of aromatic and aliphatic functional groups. The results obtained enable the design of biochars for a desired purpose, which might be solutions for agronomic and environmental issues, taking into account the effects of pyrolysis temperature and the type of waste to be processed.

Phytic Acid and Biochar: An Effective All Bio-Sourced Flame Retardant Formulation for Cotton Fabrics.

Flame retardant systems based on bio-sourced products combine quite high fire performances with the low environmental impact related to their synthesis and exploitation. In this context, this work describes a new all bio-sourced flame retardant system designed and applied to cotton fabrics. In particular, it consists of phytic acid (PA), a phosphorus-based naturally occurring molecule extracted from different plant tissues, in combination with biochar (BC), a carbon-rich solid product obtained from the thermo-chemical conversion of biomasses in an oxygen-limited environment. PA and BC were mixed together at a 1:1 weight ratio in an aqueous medium, and applied to cotton at different loadings. As revealed by flammability and forced combustion tests, this bio-sourced system was able to provide significant improvements in flame retardance of cotton, even limiting the final dry add-on on the treated fabrics at 8 wt.% only. The so-treated fabrics were capable to achieve self-extinction in both horizontal and vertical flame spread tests; besides, they did not ignite under the exposure to 35 kW/m2 irradiative heat flux. Conversely, the proposed flame retardant treatment did not show a high washing fastness, though the washed flame retarded fabrics still exhibited a better flame retardant behavior than untreated cotton.

Carbonization effect on EFB briquettes prepared with different type of binders

Biomass energy is gaining public interest as a result of the environmental impacts and depletion of fossil fuel resources. Thus, biomass briquettes have emerged as an attractive option due to its huge renewable energy potential. The biomass briquettes are used for thermal applications because it can produce complete combustion as it has consistent quality and high burning efficiency. However, the quality of the briquettes can be added by application of carbonization treatment method. Carbonization of biomass is a waste treatment process in which a biomass is heated in an oxygen-free or oxygen-limited environment. In this study, carbonized EFB was blended with binders and densified into briquettes. The mixing ratio of binders to carbonize EFB were fixed at 20%. The effect of the carbonization treatment on the briquette properties and combustion characteristics was studied through proximate and ultimate analysis while high heating value (HHV) was analyses by using bomb calorimeter. To explore the potential of carbonized EFB briquettes, the results were compared to untreated EFB briquettes. Results indicate briquette TS2 as the optimum formulation since it owned moderate physicochemical properties. In addition, the briquette had highest HHV of 23.62 MJ/kg which is approximately 30% higher than briquette prepared from untreated EFB. Overall, carbonized EFB blended with tapioca starch was found to improve the briquette quality and enhance the possibility to use as syngas production.

Carbon Nanofibrous Sponge Made from Hydrothermally Generated Biochar and Electrospun Polymer Nanofibers

The objective of this study was to convert biochar, a byproduct generated from the hydrothermal process (in oxygen-limited environment) of biomass (e.g., corn stover), into value-added product. In specific, three-dimensional (3D) biochar-containing precursor sponge, which was made by using electrospun polymer nanofibers as skeleton support, was fabricated via an innovative approach. The weight ratio of biochar to polymer (in the precursor sponge) was 2/1, and it appeared that the biochar weight ratio could be further increased. Upon heat treatments (i.e., stabilization in air and carbonization in argon), the precursor sponge was converted into carbon nanofibrous sponge that had the porosity of ~ 90 vol%, the BET surface area of ~ 51.7 m2 g− 1, and the carbon content of ~ 95 wt%; and it was mechanically elastic/resilient. The electrochemical study indicated that, the carbon nanofibrous sponge could be utilized for making supercapacitor electrode with excellent rate capability and high kinetic performance. This study would not only demonstrate a high-value application of hydrothermally generated biochar, but also provide a facile while novel approach for the fabrication of carbon nanofibrous sponge which could be potentially used for various applications (particularly the energy storage application).

Variability of Physical and Chemical Properties of TLUD Stove Derived Biochars

Biochar is a carbon-rich organic material, obtained by the thermochemical conversion of biomass in an oxygen-limited environment, used as a soil amendment to stimulate soil fertility and improve soil quality. There is a clear need in developing countries for access to low cost, low technology options for biochar production, for example, top-lit updraft (TLUD) stoves, which are popular and spread worldwide. However, TLUD biochars are inevitably very variable in their properties for a variety of reasons. We present laboratory triplicate tests carried out on TLUD biochars obtained from waste pinewood and a Guadua bamboo. Analyzed properties include specific surface area (A-BET), porosity, skeletal density, hydrophobicity, proximal and elemental composition, cation exchange capacity (CEC), relative liming capacity and pH. SEM images of the bamboo and wood biochars are compared. The biochars were mixed with composted human excreta at 5% and 10% biochar content, and available water content (AWC) was analyzed. Operating temperatures in the TLUD were recorded, showing different behaviors among the feedstocks during the process. Differences in operating temperatures during charring of the bamboo samples seem to have led to differences in A-BET, hydrophobicity and CEC, following unprecedented trends. For the mixtures of the biochars with compost, at 5% biochar no significant differences were observed for AWC. However, in the 10% biochar mixtures, bamboo biochar showed an unexpectedly high AWC. Overall, variations of chemical and physical properties between bamboo biochars were greater, while pinewood biochars showed similar properties, consistent with more homogeneous charring temperatures.

Electric fish turn down the power

Animals have all sorts of neat tricks to find their way in the dark. Bats have sonar, ants follow their noses, and some fishes surround themselves with electric fields that can detect nearby objects. Electrical navigation is wonderful for fishes that live in murky water, but it comes at a cost – electricity is expensive to generate and can represent almost a third of the overall energy budget in these fishes. When conditions are good, paying this cost doesn't seem to be a problem. But electrical sensing is most useful in murky and stagnant habitats that also tend to be low in oxygen. Oxygen is critical for fuelling metabolic energy production and survival in oxygen-limited environments often, therefore, depends on the ability of animals to reduce their metabolic rates. How do electric fishes balance this energetic budget and deal with the expense of electricity generation in the face of severe oxygen austerity?A new study, led by Shelby Clarke at McGill University, Canada, has unravelled the details of this trade-off by studying the electric fish Petrocephalus degeni. The authors captured wild fish from a low-oxygen Ugandan swamp and brought them into a lakeside laboratory, where they measured metabolic rate and electricity production first under conditions of abundant oxygen and then after the fish were challenged with low-oxygen conditions.As oxygen levels decreased in the experimental chamber, electricity production initially remained steady. However, under more severe conditions – when about 80% of the oxygen was gone – electrical activity began to decrease. The energy saved from minimizing electrical output could then be allocated to other vital processes, allowing the fish to continue to obtain enough oxygen to maintain normal metabolism until almost 90% of the oxygen was gone from the water. Amazingly, even below this critical point where the fish could not breathe as much oxygen as they required, electrical production did not cease despite its high energetic cost. Low levels of electricity persisted, perhaps representing a desperate attempt to find an escape route.If electrical activity is constrained by oxygen supply, the authors reasoned the electric fish should get even more electric if oxygen is abundant. To test this idea, Clarke moved electric fish from their typical low-oxygen swampy habitat to a life of luxury in well-aerated aquariums. After several weeks in this housing arrangement, electrical production was indeed higher than in fish from the harsh wild conditions. However, the ability of these pampered fish to tolerate low-oxygen conditions was diminished. The authors conclude that when these electric fish have easy access to oxygen, they spend less energy on the organs used to acquire more of the gas, such as the heart, gills or blood. Instead, the energy is allocated to increased electrical capacity that presumably improves their ability to perceive their physical environment.Like any utility company, electric fish must continually evaluate the budgetary landscape when deciding how much to invest in electricity production. And, while the mechanistic details of electrical output regulation remain to be discovered, it is clear that these fish have an impressive ability to re-organize their power system over both the short and long term, allowing them to cope with whatever conditions nature throws their way.

Comparison of adsorption of biochar from agricultural wastes on methylene blue and Pb2+

Biochar was prepared from agricultural plant waste, including corn straw (MS), sunflower straw (SS), wheat straw (WS), orange peel (OS), sunflower seed shell (SSS), and chestnut shell (CS) at low temperature in a partially oxygen-limited environment. These biochars were used to adsorb heavy metals and organic pollutants. The results showed that biochar having suitable surface area and microporous area could be obtained from the raw materials at 300 °C under partial oxygen limitation. The total porosity of biochar prepared from corn straw (MS) was 92.8%, and the removal of Pb2+ was 78.6 mg/g. The obtained biochar had good adsorption properties for methylene blue and Pb2+ water of different concentrations, and the adsorption performance of biochar prepared from crop straw was better than that of biochar prepared from plant peel. Thus, it was feasible to prepare biochar and to adsorb harmful substances in water through this process. This study promotes the recycling of agricultural wastes and simplifies the preparation of carbon adsorbents.

Application of stable isotopes and dissolved ions for monitoring landfill leachate contamination.

We evaluated groundwater contamination by landfill leachate at a municipal landfill and characterized isotopic and hydrogeochemical evidence of the degradation and natural attenuation of buried organic matter at the study site. Dissolved ion content was generally much higher in the leachate than in the surrounding groundwater. The leachate was characterized by highly elevated bicarbonate and ammonium levels and a lack of nitrate and sulfate, indicating generation under anoxic conditions. Leachate δD and δ13CDIC values were much higher than those of the surrounding groundwater; some groundwater samples near the landfill showed a significant contamination by the leachate plume. Hydrochemical characteristics of the groundwater suggest that aquifer geology in the study area plays a key role in controlling the natural attenuation of leachate plumes in this oxygen-limited environment.

SEDIMENTOLOGY AND CARBON ISOTOPE (δ13C) STRATIGRAPHY OF SILURIAN–DEVONIAN BOUNDARY INTERVAL STRATA, APPALACHIAN BASIN (PENNSYLVANIA, USA)

ABSTRACTSilurian–Devonian boundary interval strata deposited during the expansion of land plants record a major perturbation of the carbon cycle, the global Klonk Event, one of the largest carbon isotope excursions during the Phanerozoic. In the Appalachian Basin, these marine strata record the regional buildup to the Acadian Orogeny. This study reports new sedimentologic, paleontologic, ichnologic, and carbon isotope data from an exceptional quarry exposure in central Pennsylvania, USA, a historically understudied area between better-documented outcrops &gt;500 km away to the southwest (West Virginia, Virginia, Maryland) and northeast (New York). Facies spanning the continuous 113-m thick outcrop are dominantly carbonate and fine-grained siliciclastic strata interpreted as being deposited in supratidal through subtidal environments, including oxygen-limited environments below storm wave base. They record parts of three transgressive-regressive cycles, in the (1) upper Silurian Tonoloway Formation, (2) upper Silurian–Lower Devonian Keyser Formation through lower Mandata Member of the Old Port Formation, and (3) Lower Devonian Mandata through Ridgeley Members of the Old Port Formation. Micrite matrix δ13Ccarb analyses exhibit a large, positive δ13Ccarb excursion (&gt;5‰ amplitude). Outcrops of this interval in the Appalachian Basin occur in two belts, between which correlation has been historically challenging. The regional correlation presented herein is based on carbon-isotope trends and is more consistent with published conodont biostratigraphy and volcanic ash ages, an improvement over published correlations based on lithostratigraphy. Transgressive-regressive trends at the central Pennsylvania study site are not consistent with regional trends, indicating that local controls (tectonics, sediment supply) rather than global (eustasy) dominated depositional patterns in the Silurian–Devonian boundary interval in the Appalachian Basin.

The sRNA DicF integrates oxygen sensing to enhance enterohemorrhagic Escherichia coli virulence via distinctive RNA control mechanisms

To establish infection, enteric pathogens integrate environmental cues to navigate the gastrointestinal tract (GIT) and precisely control expression of virulence determinants. During passage through the GIT, pathogens encounter relatively high levels of oxygen in the small intestine before transit to the oxygen-limited environment of the colon. However, how bacterial pathogens sense oxygen availability and coordinate expression of virulence traits is not resolved. Here, we demonstrate that enterohemorrhagic Escherichia coli O157:H7 (EHEC) regulates virulence via the oxygen-responsive small RNA DicF. Under oxygen-limited conditions, DicF enhances global expression of the EHEC type three secretion system, which is a key virulence factor required for host colonization, through the transcriptional activator PchA. Mechanistically, the pchA coding sequence (CDS) base pairs with the 5' untranslated region of the mRNA to sequester the ribosome binding site (RBS) and inhibit translation. DicF disrupts pchA cis-interactions by binding to the pchA CDS, thereby unmasking the pchA RBS and promoting PchA expression. These findings uncover a feed-forward regulatory pathway that involves distinctive mechanisms of RNA-based regulation and that provides spatiotemporal control of EHEC virulence.

Biogas Plant Installation in the Region of Brandenburg, Germany: Environmental Impacts-Safety Aspects and Risk Application

A significant renewable source nowadays is biomass that covers the 12 % worldwide of the energy needs. The national German market belongs to one of the world leaders regarding the biogas use and production. Around 7800 biogas power plants are located in the Germany in a corresponding capacity of 3.5 GW. The World Bioenergy Association supports that up to 90% of the total bioenergy consumption is going for traditional uses like cooking and heating. The main biomass resources are mainly used for heat and electricity production or for generating secondary energy barriers such as biogas or biofuels. We have a variation of biomass residues that main categories are agricultural, waste, forestry and industrial residues. All the types of the residues have the ability to be used as input in biogas power plants for biogas generation. In the production of biogas the technological process which is used is known as anaerobic digestion. The process is microbiological and during operation the organic material is decomposing in oxygen limited environment. In the biogas generation technologies are given several difference substrates that all have a different environmental performance. The construction of a biogas power plant and its operation results in plenty of safety issues, possible risks and impacts in the human health, animals and the ecosystems. It is highly significant the biogas power plants to provide a safe environment for the employees. The regional state of Brandenburg has been developing regarding the renewable sources of energy. The Ministry of Environment, Health and Consumer Protection has been focused in an innovative policy considering the energy efficiency and energy conservation, however there has been emphasized the production of renewable energy

The Impact of Hydrothermal and Dilute Acid Pretreatments and Inorganic Metals on Thermal Decomposition of Agricultural Residues and Agricultural Residue Ash Properties

The impacts of hydrothermal and dilute acid pretreatments and alkali and alkaline earth metals (AAEMs) on the thermal degradation of biomass were studied. Besides, the influence of these pretreatments on the biomass ash properties was investigated. The influence of pretreatments on the biomass thermal degradation was manifested in the removal of potassium out of the biomass. The presence of potassium in the biomass catalyzed cellulose thermal degradation and increased the char percentage at temperatures higher than 380 °C. Pretreatments were effective at removing the potassium from biomass and dramatically reduced the char percentage at temperatures higher than 380 °C. It was found that the best burning temperature for biomass ash production was 500 °C because at this temperature the thermal degradation of biomass was completed under pure combustion. It was shown that when burning biomass in oxygen-limited environments, removing AAEMs, particularly potassium, will improve the quality of ash as a potential candidate for supplementary cementitious materials for concrete application.

Streptomyces coelicolor in an oxygen-limited liquid environment: adapt and escape

Streptomycetes are mycelial soil bacteria that undergo a complex developmental cycle on solid media. Spores germinate and form a branched, vegetative mycelium. Several signals trigger the formation of hydrophobic aerial hyphae that differentiate further into reproductive chains of spores. Differentiation is accompanied by the production of secondary metabolites, e.g. antibiotics.