Physiological Status and Community Composition of Microbial Mats of the Ebro Delta, Spain, by Signature Lipid Biomarkers

Abstract Physiological status of microbial mats of the Ebro Delta (Tarragona, Spain) based on the extraction of lipids considered ``signature lipid biomarkers' (SLB) from the cell membranes and walls of microorganisms has been analyzed. Data from a day–night cycle show significant differences in viable cells countings (PLFA cells counts) ranging from 1.5 × 10¹⁰ to 5.0 × 10¹⁰ cells g⁻¹ of sediment. Minimum values were observed at 18:00 and 6:00, when physicochemical conditions change drastically. The diversity of the microbial community was assessed by GC/MS analysis of phospholipid fatty acids (PLFA). The ratio of PLFA, representative of Gram-negative bacteria, comprises 47.8% of the total PLFA of the microbial mat community. The remaining PLFA was representative of Gram-positive (10.0%), anaerobic (5.7%), and eukaryotic microorganisms (5.7%), and other common lipids. Two different approaches were used as a comparative study to assess the physiological status of the microbial mats. Two parameters (cyclopropane fatty acids/ω7c monoenoic fatty acids, and measurement of the trans/cis monoenoic PLFA ratio) showed a minimum at midnight, suggesting the highest microbial activity. Higher values were observed at 18:00 and 6:00, coinciding with lower PLFA cell counts. Received: 14 May 1999; Accepted: 6 September 1999; Online Publication: 24 March 2000     

Evolution of clostridia and streptomycetes in full-scale composting facilities and pilot drums equipped with on-line temperature monitoring and aeration

The evolution of sporulating bacteria in full-scale composting facilities with online temperature monitoring has been poorly studied, although organic matter recycling increases. We analysed Clostridium perfringens and sulphite-reducing clostridia (SRC) by cultivation, and streptomycetes by real-time PCR in five full-scale, temperature-monitored and aerated composting processes, and two pilot-scale drum composters. Facilities composted woodchips, sawdust, peat, or bark amended sludge or source-separated biowaste. Streptomycetes genes of 0.21-110 × 10⁷ copies/g feed increased fast to 0.019-33 × 10⁹ copies/g, and then were equal or decreased. SRC of 0.06-2.2 × 10⁷ cfu/g feed decreased to 0-600 cfu/g, with re-growth in two facilities. End products were clean of C. perfringens, detected in sludge composts. Although processes contained large quantities of spore-forming bacteria, in the best facilities end products had the high quality. Temperature (>55 °C, >2d) was not related to the end compost quality, but relations between waste and bulking agent qualities, aeration, and processing time should be better controlled.     

Seasonal Variation in the Structure of a Marine Benthic Microbial Community

Abstract The patterns of seasonal variation in the structure of a marine benthic microbial community were examined using phospholipid fatty acid analysis (PLFA). Principal component analysis of PLFA profiles indicated a strong seasonal pattern dominated the variance within the data set. Three functional groups of microorganisms (phototrophic microeukaryotes, and two groups of anaerobic bacteria) were disproportionately abundant in the communities that mapped to either extreme of the first principle component. Phototrophic microeukaryotes were most abundant and exhibited the greatest relative abundance during periods of cold water. In contrast, the two functional groups of anaerobic bacteria showed the greatest relative abundance during times of warm water. Differential responses by these groups, and macrofaunal deposit feeders, to light intensity and water temperature were offered as the proximal causes of the observed patterns. Received: 28 April 1997; Accepted: 10 September 1997     

Comparison of signature lipid methods to determine microbial community structure in compost

The microbial community structure changes substantially during the composting process and simple methods to follow these changes can potentially be used to estimate compost maturity. In this study, two such methods, the microbial identification (MIDI) method and the ester-linked (EL) procedure to determine the composition of long-chain fatty acids, were applied to compost samples of different age. The ability of the two methods to describe the microbial succession was evaluated by comparison with phospholipid fatty acid (PLFA) analysis on the same samples.Samples were taken from a 200-l laboratory compost reactor, treating source-separated organic household waste. During the initial stages of the process, the total concentration of fatty acids in compost samples treated with the EL and MIDI methods was many times higher than with the PLFA method. This was probably due to the presence of fatty acids from the organic material in the original waste. However, this substantial difference between PLFA and the other two methods was not found later in composting. Although the PLFA method gave the most detailed information about the growth and overall succession of the microbial community, the much simpler MIDI and EL methods also successfully described the shift from the initially dominating straight chain fatty acids to iso- and anteiso branched, 10 Me branched and cyclopropane fatty acids in the later stages of the process. Thus, the MIDI and EL extraction methods appear to be suitable for analysis of microbial FAME profiles in compost, particularly in the later stages of the process.     

Microbiological aspects of biowaste during composting in a monitored compost bin

AIMS: To determine the microbial succession of the dominating taxa and functional groups of microorganisms and the total microbial activity during the composting of biowaste in a monitored process. METHODS AND RESULTS: Biowaste (vegetable, fruit and garden waste) was composted in a monitored composting bin system. During the process, taxonomic and functional subpopulations of microorganisms were enumerated, and dominating colonies were isolated and identified. All counts decreased during the thermophilic phase of the composting, but increased again when the temperature declined. Total microbial activity, measured with an enzyme activity assay, decreased during the thermophilic phase, increased substantially thereafter, and decreased again during maturation. Bacteria dominated during the thermophilic phase while fungi, streptomycetes and yeasts were below the detection limit. Different bacterial populations were found in the thermophilic and mesophilic phases. In fresh wastes and during the peak-heating phase, all bacterial isolates were bacilli. During the cooling and maturation phase the bacterial diversity increased, including also other Gram-positive and Gram-negative bacteria. Among the fungi, Aspergillus spp. and Mucor spp. were predominant after the thermophilic phase. CONCLUSIONS: The microbial abundance, composition and activity changed substantially during composting and compost maturity was correlated with high microbial diversity and low activity. SIGNIFICANCE AND IMPACT OF THE STUDY: A more complete overview of the whole composting process of biowaste, based on microbial counts, species diversity and functional groups and abiotic parameters is presented, and the potential of a simple enzyme assay to measure total microbial activity was demonstrated.     

Co-composting of pharmaceutical wastes in soil

AIMS: Soils at a commercial facility had become contaminated with the pharmaceutical chemical residues, Probenecid and Methaqualone, and required remediation. METHODS AND RESULTS: Soil composting was investigated as an alternative to incineration for treatment. In laboratory trials, a factorial experimental design was used to evaluate organic matter amendment type and concentration, and incubation temperature. In pilot scale trials, Probenecid was reduced from 5100 mg kg(-1) to < 10 mg kg(-1) within 20 weeks in mesophilic treatments. An 8 tonne pilot scale treatment confirmed that thermophilic composting was effective under field conditions. In the full-scale treatment, 180 tonnes of soil were composted. Initial concentrations of the major contaminants in the full-scale compost treatment were 1160 mg kg(-1) and 210 mg kg(-1), for Probenecid and Methaqualone, respectively. Probenecid concentration reached the target level of 100 mg kg(-1) in 6 weeks, and removal of Methaqualone to < 100 mg kg(-1) was achieved after 14 weeks. CONCLUSION: Co-composting was effective in reducing soil concentrations of Probenecid and Methaqualone residues to acceptable values. SIGNIFICANCE AND IMPACT OF THE STUDY: Co-composting is a technology that has application in the remediation of pharmaceutical contaminants in soil.     

Determinants of Soil Microbial Communities: Effects of Agricultural Management, Season, and Soil Type on Phospholipid Fatty Acid Profiles

Abstract Phospholipid fatty acid (PLFA) profiles were measured in soils from organic, low-input, and conventional farming systems that are part of the long term Sustainable Agriculture Farming Systems (SAFS) Project. The farming systems differ in whether their source of fertilizer is mineral or organic, and in whether a winter cover crop is grown. Sustained increases in microbial biomass resulting from high organic matter inputs have been observed in the organic and low-input systems. PLFA profiles were compared to ascertain whether previously observed changes in biomass were accompanied by a change in the composition of the microbial community. In addition, the relative importance of environmental variables on PLFA profiles was determined. Redundancy analysis ordination showed that PLFA profiles from organic and conventional systems were significantly different from April to July. On ordination plots, PLFA profiles from the low-input system fell between organic and conventional systems on most sample dates. A group of fatty acids (i14:0, a15:0, 16:1ω7c, 16:1ω5c, 14:0, and 18:2ω6c) was enriched in the organic plots throughout the sampling period, and another group (10Me16:0, 2OH 16:1 and 10Me17:0) was consistently lower in relative abundance in the organic system. In addition, another group (15:0, a17:0, i16:0, 17:0, and 10Me18:0) was enriched over the short term in the organic plots after compost incorporation. The relative importance of various environmental variables in governing the composition of microbial communities could be ranked in the order: soil type > time > specific farming operation (e.g., cover crop incorporation or sidedressing with mineral fertilizer) > management system > spatial variation in the field. Measures of the microbial community and soil properties (including microbial biomass carbon and nitrogen, substrate induced respiration, basal respiration, potentially mineralizable nitrogen, soil nitrate and ammonium, and soil moisture) were seldom associated with the variation in the PLFA profiles. Received: 3 February 1997; Accepted: 7 August 1997     

Heavy metal contamination of a mixed waste compost: Metal speciation and fate

The aims of this study were to assess changes in heavy metal availability in two contrasting feedstocks during aerobic composting, and the availability of said metals in the finished composts. A high C-to-N ratio mixed biodegradable municipal solid waste (MSW) feedstock was successfully composted on its own and in combination with green waste. Changes in heavy metal speciation throughout the composting process were studied using the modified BCR sequential extraction protocol. It was found that total Cu, Pb and Zn concentrations increased over time due to the progressive mineralization of the compost feedstock. Metals were fractionated differently within the two feedstocks, although only Cu showed significant redistribution (mostly to the oxidisable fraction) over the 5 month composting period. The MSW-derived composts performed comparably with other commercially-available composts in a series of plant growth trials. Plant metal accumulation was not influenced by the heavy metals present in the MSW-derived compost implying that they are not plant available. It is recommended that these relatively low value/quality composts may be used for remediation of acidic heavy metal contaminated sites.     

Microbiological parameters as indicators of compost maturity

AIMS: The objectives of this study were to determine the changes of microbial properties of pig manure collected from pens with different management strategies and composted using different turning and moisture regimes; relate their association with humification parameters and compost temperature; and identify the most suitable microbial indicators of compost maturity. METHODS AND RESULTS: Six different microbial parameters, including total bacterial count, oxygen consumption rate, ATP content, dehydrogenase activity, and microbial biomass C and N, along with humification parameters [humic acid (HA), fulvic acid (FA) and HA : FA ratio] and compost temperature were monitored during composting. Significant positive correlations were found between temperature and microbial properties, including O2 consumption rate, ATP content, dehydrogenase activity, and microbial biomass N. The humification parameters also showed significant correlations with microbial properties of the manure compost. For instance, HA contents of pig manures was positively correlated with total aerobic heterotrophs, and microbial biomass N and C; and negatively correlated with O2 consumption rate, ATP content, and dehydrogenase activity. Among the six microbial parameters examined, dehydrogenase activity was the most important factor affecting compost temperature and humification parameters. Composting strategies employed in this study affected the speed of composting and time of maturation. If the moisture content is maintained weekly at 60% with a 4-day turning frequency, the pig manure will reach maturity in 56 days. CONCLUSIONS: The composting process went through predictable changes in temperature, microbial properties and chemical components despite differences in the initial pig manure and composting strategies used. Among the six microbial parameters used, dehydrogenase activity is the most suitable indicator of compost maturity. Compared with respiration rate, ATP content and microbial biomass procedures, dehydrogenase activity is the simplest, quickest, and cheapest method that can be used to monitor the stability and maturity of composts. SIGNIFICANCE AND IMPACT OF THE STUDY: The results presented here show that microbial parameters can be used in revealing differences between composts and compost maturity. The statistical relationship established between humification parameters and microbial parameters, particularly dehydrogenase activity, demonstrates that it is possible to monitor the composting process more easily and rapidly by avoiding longer and more expensive analytical procedures.     

Characterization of Microbial Consortia in Paddy Rice Soil by Phospholipid Analysis

Abstract Microbial biomass and community structure in paddy rice soil during the vegetation period of rice were estimated by analysis of their phospholipid fatty acids (PLFA), hydroxy fatty acids of lipopolysaccharides (LPS-HYFA), and phospholipid ether lipids (PLEL) directly extracted from the soil. A clear change in the composition of the community structure at different sampling periods was observed, indicated by the principal component analysis of the PLFA. A dramatic decline of ester-linked PLFA was observed in the soil samples taken at the second sampling time. In contrast to the ester-linked PLFA, the non-ester-linked PLFA composition did not change. The hydroxy fatty acids of lipopolysaccharides as well as ether lipids decreased consecutively during the observation period. Total microbial abundance was estimated to be (4.1–7.3) × 10⁹ cells g^-1 soil (dry weight). About 44% account for aerobic and 32% for facultative anaerobic bacteria, and 24% for archaea, on average. According to the profile and patterns of PLFA in the soil sample, it may be suggested that the paddy soil at the August sampling period contained more abundant facultative anaerobic bacteria (ca. 36%) and archaea (ca. 37%), but the total microbial biomass was significantly lower than in the remaining sampling periods. As the plant approached maturity, the microbial community structure in the soil changed to contain more abundant Gram-negative bacteria and methanotrophs. Received: 23 September 1999; Accepted: 28 February 2000; Online Publication: 12 May 2000     

Microbial Communities in High and Low Recharge Environments: Implications for Microbial Transport in the Vadose Zone

Abstract Microbial communities along vertical transects in the unsaturated zone were evaluated at five sites in the Pasco Basin, in southeastern Washington State. Sites with contrasting recharge rates were chosen to maximize or minimize the potential for microbial transport. Pore water ages along the vertical transects were established using natural chloride tracers, and ranged from modern to either ∼15,000 yBP (years before present) or ∼30,000 yBP at the two low-recharge sites. Unsaturated flow processes were short-circuited by preferential flow at two of the three high-recharge sites, resulting in rapid movement of water through the vertical transects. Microbial numbers and biomass, based on plate counts, and phospholipid fatty acid (PLFA) concentrations decreased with depth at all sites. The majority (55–90%) of the culturable chemoheterotrophs recovered from most samples were streptomycete bacteria. 16S rRNA gene sequence and MIDI analyses indicated that 75% of the remaining isolates were Gram-positive bacteria (most likely species of Arthrobacter and Bacillus) 25% were Gram-negative bacteria (probably members of several genera in the alpha- and gamma-Proteobacteria). Comparison of microbial communities at low-recharge sites vs. high-recharge sites, where preferential flow occurs, revealed several differences that might be attributed to vertical transport of microbial cells at the high-recharge sites. Plate counts and PLFA analyses indicated that the proportion of streptomycetes, which were abundant at the surface but present in the subsurface as spores, decreased, or remained constant, with depth at the low-recharge sites, but increased with depth at the high-recharge sites. PLFA analyses also indicated that Gram-negative bacteria displayed increased nutrient stress with depth at the high-recharge sites characterized by preferential flow, but not at the low recharge site. This may be a result of advective transport of microbes to depths where it was difficult for them to compete effectively with the established community. Moreover, PLFA community structure profiles fluctuated considerably with depth at the low-recharge sites, but not at the high-recharge sites. This might be expected if transport were distributing the microbial community along the vertical profile at the high-recharge sites. In contrast to the high-recharge sites at which preferential flow occurs, filtration likely prevented vertical transport of microorganisms at the high-recharge site that was characterized by unsaturated flow. Received: 6 November 1996; Accepted: 9 May 1997     

Novel static composting method for bioremediation of olive mill waste

This paper presents results obtained on the evaluation of static composting process aimed at bioremediation of the hazardous solid olive mill waste (OMW). The static composting process carried out in gas-permeable polyethylene bags followed the fluctuating temperature and oxygen profiles similar to those seen in aerated composting systems. Static composting resulted in apparent increases and decreases in values for total nitrogen and C:N ratios respectively during the process. The amount of nitrogen (>3%) in the composting end product was in agreement with the Italian legislation (Decreto Legislativo 29 aprile 2010, n. 75) specification for nitrogen fertilizer. A gradual decrease in polyphenols during the storage of compost resulted in a non-phytotoxic composted organic matter high in humic substances. Different respirometric tests also stated high biological stability of the end compost product.     

Microbial dynamics and enzyme activities during rapid composting of municipal solid waste - a compost maturity analysis perspective

An investigation was carried out in the laboratory to find out the microbial dynamics and enzyme activities during rapid composting of municipal solid waste (MSW). Various treatments such as aeration (A), addition of chemical agents (glucose (G) and acetic acid (AA) and application of cellulolytic microbial (M) inoculum (Phanerochaete chrysosporium and Trichoderma reesei) were used to facilitate the decomposition of MSW. The result of the present investigation revealed that the degradation of organic substrates were quick (within 9-12 days) in case of rapid composting as indicated by the reduction (below 20) in C/N ratio. Whereas, normal composting took more than 20 days to attain C/N ratio of below 20. Estimation of selected enzymes (amylase, protease, phosphatase and cellulase) provided information on the substrate specific degradation profiles of various labile substrates contained in organic waste.     

微生物在有机固废堆肥中的作用与应用

好氧堆肥是实现有机固体废弃物资源化利用的主流处理方式.堆肥腐熟是一个由微生物主导的生理生化过程,堆料通过微生物发酵实现矿质化、腐殖化和无害化,转变成腐熟的有机肥.传统的好氧堆肥存在发酵周期长、养分损失、恶臭及温室气体排放等不足.在堆肥过程中添加微生物是弥补传统好氧堆肥缺陷、提高堆肥品质和功效的有效方法.近年来,国内外在...     

Plant functional group richness-affected microbial community structure and function in a full-scale constructed wetland

We examined the linkages between plant functional group richness and microbial community structure and functions in a full-scale vertical flow constructed wetland (VFCW), where five plant functional group richness levels (including zero (control), one, two, three and four functional groups) were applied. Most diagnostic phospholipid fatty acid (PLFA) abundances and enzyme activities were higher in planted treatments than in the control (p < 0.05). Among the diagnostic PLFAs determined, only the fungal PLFA (18:2ω6,9) abundance was related to plant functional group richness level (p < 0.05). For the enzyme activities determined, dehydrogenase, invertase, urease and acid phosphatase activities responded positively to plant functional group richness (p < 0.05). Redundancy analysis (RDA) identified that the Gram-positive and Gram-negative bacteria, actinomycetes and fungi abundances affected enzyme activities. Principal component analyses (PCAs) revealed that the enzyme profiles had greater resolving power in distinguishing plant functional group richness than the PLFA profiles. We conclude that plant functional group richness was closely linked to microbial community structure and functions in the full-scale VFCW we studied.     

生物垃圾堆肥的过程研究及腐熟度评价

目的：研究静态强制通风发酵工艺对合肥市农贸市场的生物废弃物进行好氧堆肥处理过程的物质变化和腐熟效果。方法：分析发酵过程中温度、含水率、挥发分含量、纤维素、半纤维素和木质素含量等物理指标和化学指标。结果：一次发酵中堆肥的温度在55℃以上的有3d,经过一次发酵和二次发酵,堆肥中挥发分含量由85.4%降低到51.2%。纤维素的含量由20.90%减少到15.48%,半纤维素的含量由7.20%减少到1.36%,,纤维素、半纤维素在二次发酵中降解率比一次发酵的小,木质素虽在一次发酵中基本没有降解。但在二次发酵中得到有效降解,木质素含量由8.30%减少到5.38%。堆肥后物料在70d堆肥后,基本上达到腐熟程度。结论：温度、含水率、挥发性物质、淀粉实验、生物可降解度实验等指标检测可以评价静态强制通风发酵工艺对合肥市农贸市场的生物废弃物进行好氧堆肥处理过程的物质变化和腐熟效果。     

Relating Quinone Profile to the Aerobic Biodegradation in Thermophilic Composting Processes of Cattle Manure with Various Bulking Agents

Summary Cattle manure was composted aerobically with various bulking agents (rice straw, vermiculite, sawdust or waste paper) at a constant incubation temperature of 60 °C. Increased quinone content (IQC) was used to assess microbial biomass in the composted material. IQC was proportional to mass reduction (MR) (R = 0.812) and cumulative O₂ consumption (COC) (R = 0.810) irrespective of the bulking agent used, indicating that the yield of quinone was constant. Quinone yields were 0.44 ± 0.03 μmol quinone/g MR and 0.34 ± 0.02 μmol quinone/g COC. The material that was decomposed by microorganisms was considered to be mainly cattle manure. Bulking agents were not degraded within the 14 day trial period and did not affect microbial succession because composting runs with various bulking agents exhibited similar quinone yields.     

Removal of volatile organic compounds by natural materials during composting of poultry litter

The objective of this study was to reduce volatile organic compounds (VOCs) produced during composting of poultry litter. The natural zeolite, expanded perlite, pumice and expanded vermiculite as the natural materials were used for the reducing of VOCs. Composting was performed in a laboratory scale in-vessel composting plant. Poultry litter was composted for 100 d with volumetric ratio of natural materials:poultry litter of 1:10. The VOCs were tested using the FT-IR method by VOCs analyzer. Studies showed that VOCs generation was the greatest in the control treatment without any natural materials. The natural materials significantly reduced VOCs. At the end of the processes, removal efficiency was 79.73% for NZ treatment, 54.59% for EP treatment, 88.22% for P treatment and 61.53% for EV treatment. Potential of removal for VOCs on poultry litter matrix using natural materials was in order of: P>NZ>EV>EP.     

Biotransformation of 1-naphthalenesulfonic acid by the green alga Scenedesmus obliquus

Under sulfate limitation, axenic batch cultures of the green alga Scenedesmus obliquus metabolized 1-naphthalenesulfonic acid and partially used the sulfonate as a source of sulfur. The main metabolite, 1-hydroxy-2-naphthalenesulfonic acid, which was not metabolized further in the algal culture, was formed by hydroxylation of the substrate in position 1 and by migration of the sulfonic acid group to position 2 of the naphthalene ring (NIH shift). A smaller amount of 1-naphthalenesulfonic acid was desulfonated. The resulting 1-naphthol was mostly transformed into 1-naphthyl β-d-glucopyranoside. Received: 27 March 1996 / Revision received: 18 October 1996 / Accepted: 30 October 1996