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Phthalic acid esters are predominantly used as plasticizers and are industrially produced on the million ton scale per year. They exhibit endocrine-disrupting, carcinogenic, teratogenic, and mutagenic effects on wildlife and humans. For this reason, biodegradation, the major process of phthalic acid ester elimination from the environment, is of global importance. Here, we studied bacterial phthalic acid ester degradation at Saravan landfill in Hyrcanian Forests, Iran, an active disposal site with 800 tons of solid waste input per day. A di-n-butyl phthalate degrading enrichment culture was established from which Paenarthrobacter sp. strain Shss was isolated. This strain efficiently degraded 1 g L–1 di-n-butyl phthalate within 15 h with a doubling time of 5 h. In addition, dimethyl phthalate, diethyl phthalate, mono butyl phthalate, and phthalic acid where degraded to CO2, whereas diethyl hexyl phthalate did not serve as a substrate. During the biodegradation of di-n-butyl phthalate, mono-n-butyl phthalate was identified in culture supernatants by ultra-performance liquid chromatography coupled to electrospray ionization quadrupole time-of-flight mass spectrometry. In vitro assays identified two cellular esterase activities that converted di-n-butyl phthalate to mono-n-butyl phthalate, and the latter to phthalic acid, respectively. Our findings identified Paenarthrobacter sp. Shss amongst the most efficient phthalic acid esters degrading bacteria known, that possibly plays an important role in di-n-butyl phthalate elimination at a highly phthalic acid esters contaminated landfill.

The increasing use of plastics, the accumulation of phthalic acid esters (PAEs), and their derivatives in high concentrations in human environments have raised global concerns and highlighted the urgent need to purify these pollutants. In our study, consortium AnL1 with the ability to degrade phthalic acid (PA) was isolated in anaerobic conditions from Anzali international wetland (adjacent to the Caspian Sea) which is extremely polluted by phthalates. Afterward, the two strains of SHAn1 and SHAn2 with the qualities of degrading PA and denitrifying were isolated from consortium AnL1. Based on the phylogenetic analysis (16S rRNA gene), strains SHAn1 and SHAn2 were classified as Aromatoleum aromaticum (MW322985) and Ralstonia pickettii (MW290933), respectively. Biodegradation assessment of PA revealed that consortium AnL1 (1% inoculum size) with a novel composition (Ralstonia pickettii and Aromatoleum aromaticum) could degrade 86.86% of 1000 mg/L PA after 150 h. In addition, when the inoculum size increased to 5%, consortium AnL1 was able to degrade 79.96% of 3200 mg/L PA in 166 h. This research, for the first time, provides unequivocal evidence that one aerobic bacteria 'Ralstonia pickettii strain SHAn2' has a high ability to consume PA which could break down 81.59% of 2000 mg/L PA under the anaerobic and nitrate reduction (20 mM) conditions. In addition to the already proven high potency of Ralstonia pickettii in consuming organic pollutants, our study showed that this bacterium has the competence to degrade PA under anaerobic conditions and can be applied in further studies as a candidate for purification in ecosystems.

Application of barrier dispersion coatings on paperboards, which must have proper moisture and grease resistance for food applications, has always been an interesting subject for the packaging industry. In this study, paperboards were coated with a novel dispersion barrier coating prepared through mixing soy protein isolate (SPI) and polyethylene wax (PE-wax). Different characterization methods were used to study the effects of coating and its composition on the physical, mechanical, and barrier characteristics of paperboards. The results indicated that the incorporation of PE-wax into the coating formulation caused significant reduction of the viscosity of coating slurries. It had no effect on the coating weight of the samples but increased the thickness of the coated paperboards as compared with those coated with SPI only. The increase of the wax content led to a reduction of 5-16% in the tensile strength values in comparison with the uncoated paperboards. Barrier characteristics, i.e., water vapor permeability (WVP), surface wettability, and water resistance, improved by adding PE-wax. In addition, it was found that there was a critical level for the addition of PE-wax, 50% of SPI, as no oil migration was detected when the paperboards coated with SPI coatings contained less than 50% PE-wax.

This research aimed to optimize a lipopeptide biosurfactant produced from

This study aimed to investigate the combined effect of native sulfur-oxidizing bacteria and different sources of sulfur on pH, electrical conductivity, sulfate content in soil, plant growth...

After isolation of halophilic bacteria from saline soils, the effects of two superior isolates producing exopolysaccharide TP7 and TP5 was investigated on some wheat growth parameters such as shoot and root dry weight and concentration of K+, Ca2+, Na+ and K+/Na+, Ca2+/Na+ ratios under saline stress. Inoculation with bacteria (TP7, TP5 and both of strains) had a positive effect on shoot weight (74.71, 57.52 and 82.45%) at EC 8 dS m−1 and (45.26, 60.95 and 71.28%) at EC 16 dS m−1. Also, TP7 and TP5 isolates can increase plant resistance to salt and drought stresses by decreasing Na+ uptake and in 16 dS m−1 led to an increase in dry weight of root in comparison with control by 97.95, 128.29 and 193.53%, respectively. In higher-salinity treatments, all of treatments (TP5, TP7 and both of strains) had a significant effect on K+ concentration, especially in EC 16 dS m−1 by 29.58, 45.94 and 53.56% and 35.50, 52.37 and 58.65% in water stress and non-water stress, respectively. The determination of 16S rRNA gene sequences of isolates TP7 and TP5 showed that they are mostly close to Bacillus subtilis susp. inaquosorum (98.49% sequence similarity) and Marinobacter lipolyticus SM19 (T) (97.69% sequence similarity), respectively. Generally, results showed that these isolates can be used as a tool for reducing adverse effects of salinity and drought stresses in wheat plant.

To date, studies for bioremediation of oil-polluted hypersaline soils have been neglected or limited to specific spots. Hence, in this study, ten samples of oil field soils in the Khuzestan province of Iran were collected to evaluate bioremediation's feasibility. These samples were analyzed for their physicochemical properties as well as the most probable number of total and hydrocarbon-degrading bacteria. Thirty-nine hydrocarbon-degrading bacteria were isolated from these soils over a 1-month incubation in an MSM medium enriched with diesel oil as the sole source of carbon. As revealed by 16S-rRNA analysis, the identified strains belonged to the genera Ochrobactrum, Microbacterium, and Bacillus with a high frequency of Ochrobactrum species. Additionally, by using degenerate primers, the third group of alkB gene was detected in Ochrobactrum and Microbacterium isolates through the touchdown nested PCR method for the first time. Ochrobactrum species possessing the alkB gene showed the highest population, and therefore, the highest adaptation to harsh environmental conditions. Most isolates showed outstanding results in the ability to grow with crude and diesel oil and tolerate high salt percentages, biosurfactant production, and emulsification activity, which are considered the most effective factors in bioremediation of such environments. Considering the soil analysis, limiting factors in bioremediation like available phosphorous, and the abundance of bacteria with remediation traits in these soils, these extremely polluted environments can be refined.

A novel strategy of using microalgaeChlorella vulgarisfor simultaneous bio-treatment of petrochemical wastewater and lipid production was developed in the present study. Phycoremediation was carried out in 30 days. The profile of fatty acids was identified, and the specifications of biodiesel including saponification value, iodine value, cetane number, long-chain saturated factor, cold filter plugging point, cloud point, allylic position equivalent and bis-allylic position equivalent were predicted by BiodieselAnalyzer® software. Besides, polycyclic aromatic hydrocarbons were determined in both wastewater samples and produced lipid. The observed data showed that biodiesel fromC. vulgariswas superior to petrodiesel in terms of suitability in diesel engines. Moreover, contamination of petrochemical wastewater can influence the expression of a variety of genes in algae. To investigate the effectiveness of contamination on the expression of lipid synthesis as well as three photosynthesis genes, a real-time polymerase chain reaction assay was used to quantify transcript levels ofPsaB(photosystem I reaction center protein subunit B),psbC(an integral membrane protein component of photosystem II), andrbcL(a large subunit of ribulose-1,5-bisphosphate carboxylase oxygenase). Furthermore, the gene expression level ofaccD(acetyl-coenzyme A carboxylase carboxyl transferase subunit beta, chloroplastic) was studied to discover the effect of wastewater on lipid production. The results showed that when diluted petrochemical wastewater (50%) was used as a media forC. vulgariscultivation, these genes expression significantly increased. For 50% diluted wastewater, the maximum removal of BOD, COD, total nitrogen, and total phosphor has been 30.36%, 10.89%, 69.89%, and 92.59%, respectively.

Due to ecological importance of Anzali wetland (in south of the Caspian sea) and taking the toxicity of phthalates into consideration, which can finally find their way to human diet and pose a huge threat to human food security, the occurrence and concentration of phthalic acid esters in nine stations (27 sediment samples) in this wetland alongside their relationship with physical and chemical properties of the sediments were studied. The samples were extracted by using ultrasound assisted solvent extraction and analyzed for six major phthalates using a gas chromatograph–mass spectrometer. Results of laboratory analyses showed that concentrations of six major phthalic acid esters in the Anzali sediments ranged from 4.18 to 20.71 mg kg−1 with an average of 7.65 mg kg−1. In addition, it was found that the site of Sorkhankol was heavily polluted by phthalic acid esters especially di-(2-ethylhexyl) phthalate (20.71 mg/kg dw). The concentrations of dimethyl phthalate and diethyl phthalate) were lower than the limit of detection of the GC–MS instrument. Di-(2-ethylhexyl) phthalate and di-n-butyl phthalate were the dominant phthalic acid esters present in all examined sediments. Generally, the mean concentrations of di-(2-ethylhexyl) phthalate was well above the United States Environmental Protection Agency sediment guideline value and environmental risk limits. Furthermore, investigation of sediment chemical properties revealed that the concentrations of di-n-butyl phthalate have significant linear positive correlations with sediments organic matters.

Salinity, water scarcity in the summer season, and grazing pressure are major problems in semi-arid ecosystems in the south-east region of the Caspian Sea where the Alagol rangelands of Turkmen Sahra (Golestan province) of North East Iran suffer from over-grazing and soil loss. This study investigated the influence of biological soil crusts (biocrusts) on soil physicochemical properties. Biocrusts create complex communities of specialized organisms composed of cyanobacteria, algae, microfungi, lichens, mosses and other microorganisms. Results have shown that bioencrusted soils increased levels of organic carbon, nitrogen, phosphorus, copper, and iron, and reduced pH, calcium carbonate, sodium, calcium, magnesium, sodium adsorption ratio and exchangeable sodium percentages compared to soils without biocrusts. Other positive influences of biocrusts on soil properties included increased infiltration (0.16 v. 0.081 cm min −1 for steady state rates), available water content, mean weight diameter of soil aggregates, geometric mean diameter and water stable aggregates. Bulk density was reduced under bioencrusted soils relative to non-biocrusts soils. In general, biocrusts had a positive effect on many soil properties and thus enhanced soil quality.

The current study compared the bioleaching ability of a mutated mesophilic mixed culture with that of a non-mutated mesophilic mixed culture and a moderately thermophilic mixed culture. Mutation experiments were carried out using ultrasonic and microwave irradiation on Acidithiobacillus ferrooxidans, Leptospirillum ferrooxidans, and Acidithiobacillus thiooxidans, mesophilic bacteria used in copper bioleaching. The mutational effects of irradiation were determined by measuring the ferrous iron and elemental sulfur oxidation rates. The mutated strains exhibiting the best oxidation activity were used in bioleaching tests. Bioleaching experiments using the mutated mixed culture were carried out under the same optimized operational conditions as for the non-mutated mesophilic mixed culture. The bioleaching results were compared to copper recovery obtained by the moderately thermophilic mixed culture. The copper recovery achieved by the non-mutated mesophilic mixed culture was 34.2% after 30 days and increased to 39.06 and 37.21% for ultrasonic- and microwave-mutated mesophilic mixed cultures, respectively. The bioleaching rate increased using mutated mesophilic mixed cultures, such that the copper recovery for the ultrasonically mutated mixed culture reached 34.01% after 12 days and for the microwave-irradiated mixed culture reached 33.15% after 15 days. The results of bioleaching experiments using mutated mesophilic mixed cultures under optimized operational conditions showed that the copper recovery attained was 49.12 and 44.36% for mesophilic mixed cultures mutated by ultrasound and microwaves, respectively. These were comparable with the maximum copper recovery obtained by the moderately thermophilic mixed culture which was 49.8%, especially for the ultrasonically mutated mixed culture.

Considering the high concentration of phthalic acid esters (PAEs) in Anzali international wetland, up to 40 times higher than the environmental risk limit, the aim of this study was to obtain an effective consortium and native bacteria in the degradation of diethyl hexyl phthalate (DEHP) from sediments of this ecosystem. For this purpose, sediments of 9 stations of Anzali wetland were enriched with PAEs in waterlogged conditions at 30 °C. The results showed that the consortium An6 (containing two cultivable bacteria with phthalate degradation ability, Pseudomonas putida strain ShA (MN298858), and Gordonia alkanivorans strain Sh6 (MK460262.1)) could biodegrade 100, 100, 90.57, and 58.73% of a mixture of DMP, DEP, DBP, and DEHP at high concentration (2000 mg/L each), respectively. The separate DEHP biodegradation by the above consortium showed that it could degrade 97% of 500 mg/L of DEHP in less than 3 days. Additionally, phthalic acid (PA) and monoethyl hexyl phthalate (MEHP) as intermediate products of DEHP biodegradation were identified by UPLC-Q-TOF-MS. Phthalate consumption patterns of strains ShA and Sh6 indicate that there is a possible complementary effect among these bacteria in PAEs biodegradation. The ability of consortium An6 belonging to the most polluted area (20–43 mg/Kg DEHP) of this wetland to degrade DEHP could be caused by the exposure of the microbial community of this area to PAEs over time that gives rise to a possible adaptation. Based on the findings, consortium An6 (with novel composition) and isolated bacteria can be suggested for the efficient remediating of PAEs in the different ecosystems.

In the present study, 100 bacterial strains were isolated from the soil and tested for siderophore producing ability. Among siderophore producing bacteria, three superior isolates with the highest level of siderophore (F13, F58 and F66) selected for further study. Production of lecithinase, arginine dehydrolase, catalase, oxidase, hydrogen cyanide, indole acetic acid, solubilization of phosphate, gelatin hydrolysis, oxidative/fermentative, motility and gram staining by these strains was evaluated. In greenhouse experiment, the ability of selected isolates in solubilizing insoluble iron-containing compounds was examined at three moisture levels (0.45–0.6, 0.6–0.7 and 0.7–0.85 field capacity). Results showed that isolates F13 and F66 have greatest effects on chlorophyll amount and shoot dry weight compared to isolate F58. On average, iron concentration of sunflower in the presence of bacteria was 2.85-fold more than control, while it was 1.88-fold for roots. In addition, bacterial treatments enhanced resistance to water stress in sunflower. Based on biochemical tests and by comparison of 16S rRNA sequences, the F13, F58 and F66 isolates were closely related to Pseudomonas spp., Enterobacter spp. and Bacillus Sporothernodurans, respectively.

A diazinon-degrading bacterium was isolated from paddy soils under flooded conditions. Biochemical characterization and 16S rRNA sequencing showed the isolate was an oxidase-positive Stenotrophomonas maltophilia. The isolate could grow on a mineral salt medium (MSM) supplemented with diazinon as the main carbon source (50 µg ml−1) and dissipate the pesticide in a simple first-order manner with DT50 and DT90 of 4.54 and 15.09 days, respectively. The addition of glucose favored the bacterial growth and reduced the pesticide’s DT50 and DT90 to 3.39 and 11.27 days, respectively. The dissipation of diazinon in MSM was accompanied by a slight reduction of the pH which was more significant in the glucose-treated media. FTIR analysis proved the separation of the heterocyclic leaving group by hydrolyzing the ester bond and aerobic cleavage of the aromatic ring as the main pathways of diazinon degradation in the MSM. The dissipation of diazinon (150 µg g−1) in the inoculated sterilized flooded paddy soils was biphasic, and based on this, only 31.55 µg g−1 of the initial concentration declined with a faster rate while the rest of the residue dissipated slowly as the adsorbed phase. In the non-inoculated non-sterilized soils, diazinon dissipated more slowly with an initial lag phase.

One of the limiting factors of soil fertility is contamination with petroleum hydrocarbons, which has affected soil fertility's effective biological activity, such as the symbiosis of nitrogen fixing bacteria with legumes. In this study, some petroleum hydrocarbons' effect on the nodulation of Rhizobium sp. in alfalfa roots under greenhouse conditions was evaluated. For this purpose, 25 bacterial isolates were isolated from alfalfa surface-sterilized root nodules, 5 of which could grow in yeast mannitol media containing crude oil up to 5%. These strains also had the ability to coexist with alfalfa roots and form nodules under in-vitro condition. Isolate B20 formed the highest number of nodules on alfalfa roots at concentrations of 1, 3, and 5% crude oil, which according to the 16S rRNA gene sequencing result, belonged to Ensifer meliloti. Then the effect of different concentration of crude oil (1-3-5% v/w), paraffin (1-3-5% v/w), toluene (50-100-200 ppm), naphthalene (50-100-200 ppm), and phenanthrene (50-100-200 ppm) was investigated on alfalfa growth in the presence of Ensifer meliloti. According to the results, the highest number of nodules (53.33) was observed in the control treatment, and the lowest number of nodules (14.66) was observed at the concentration of 200 mg/kg of phenanthrene. As the number of benzene rings increased, or the pollutant concentration increased, plant growth decreased as assayed by root and shoot biomass, plant nitrogen, number of root nodules, and soil microbial respiration. Contaminants or metabolites produced by the activity of soil microorganisms may inhibit the nodulation activity of Ensifer meliloti.

This investigation was carried out for evaluation of indole-3-acetic acid production by bacteria under salinity and salinity–sodicity stress. A total of 298 bacteria were isolated from soils with different levels of electrical conductivity and sodium adsorption ratio. Then, ability of indole-3-acetic acid production under salinity, salinity–sodicity and l-tryptophan concentrations was analyzed. The results indicated that the ability of growth and indole-3-acetic acid production among bacteria was significantly affected by salinity, salinity–sodicity and l-tryptophan concentration. The one of the bacterial species, Arthrobacter siccitolerans, that were isolated from saline–sodic soils can adjust its indole-3-acetic acid production to different levels of salinity and salinity–sodicity stress conditions. Also, its l-TRP use efficiency under salinity–sodicity stress was 5.01% and reported as the most efficient bacterium. Seed inoculation of A. siccitolerans enhanced wheat aerial and root dry matter under salinity–sodicity stress with respect to control by 10.03 and 15.17%, respectively. The study indicates the different effects of salinity–sodicity on indole-3-acetic acid indole-3-acetic acid production and the potential of A. siccitolerans for production of indole-3-acetic acid and enhancing growth of wheat under salinity and salinity–sodicity stress.

Cellulolytic bacteria have a bio-activating role in the composting process. A study was carried out to isolate and identify cellulolytic bacteria from various sources. The isolates were cultured in the carboxymethyl cellulose (CMC) agar medium and incubated at 30°C for 3–7 days. Based on morphological characteristics of the isolates, maximum diameter of a clear zone around the colony and maximum cellulolytic activity, eight isolate were selected for further studies regarding composting experiments.Molecular tests based on PCR amplification and sequencing of 16S rRNA gene of isolates showed the closest phylogenetic similarity with the species of Stenotrophomonas rhizophila DSM14405 (99.8%), Brevibacterium halotolerans DSM8802 (99.6%), Achromobacter marplatensis B2 (99.8%), Bacillus methylotrophicus CBMB205 (100%), Pseudomonas azotoformans IAM 1603 (99.7%), Bacillus sonorensis NBRC 101234 (99.8%), Bacillus subtilis KCTC 13429 (100%) and Ochrobactrum thiophenivorans DSM 7216 (99.3%). The study of the...

Plant growth-promoting rhizobacteria (PGPR) are soil bacteria that are able to colonize rhizosphere and to enhance plant growth by means of a wide variety of mechanisms. In the present study, Myristica yunnanensis and Stenotrophomonas chelatiphaga strains were recognized as new records in Iran flora. According to the results, these strains significantly affected plants’ zinc and phosphorous contents which could be due to the production of phytosiderophore. Siderophore-producing bacteria increased canola zinc (Zn) content as strategy-I plant, while in maize, it can be said that probably the effect of phytosiderophore produced by plant on increasing root and shoot Zn content was more than siderophore produced by bacteria. These isolates could be used as bio-input for improving the plant productivity as a substitute to chemical fertilizers and also to correct the nutrient deficiencies in canola and maize for sustainable agriculture.

Rhizospheric and endophytic bacteria are known to increase phosphorus efficiency (PE) of plant in phosphorus-deficient soils. The purpose of this research was to examine the role of rhizospheric and endophytic bacterial inoculation in increasing phosphorus acquisition efficiency (PAE) and phosphorus utilization efficiency (PUE) by solubilization of phosphate and expanding of root system. A total of 22 isolates were selected from rhizosphere and inside root of wheat (Triticum aestivum L.) plants based on plant growth promoting traits. These isolates significantly solubilized phosphorus from tri-calcium phosphate and produced indole-3-acetic acid (IAA) under in vitro condition. In pot experiment, we found that rhizospheric and endophytic bacterial inoculation improved root and shoot dry matter, grain yield, length, surface area and volume of roots. At the ripening stage, the consortium treated (co-inoculation with rhizospheric and endophytic bacteria) pots exhibited enhanced the plant height (up to 15.0% and 11.0%), shoot dry weight (up to 5.8% and 7.5%), root dry weight (up to 68% and 58%) and grain yield (up to 58.0% and 42.0%), in Marvdasht and Roshan cultivars respectively. The uptake of P was 3.61 mg pot−1 for Marvdasht cultivar and 6.44 mg pot−1 for Roshan cultivar. Inoculation with rhizospheric isolate increased PE index by 29.5% and 18.7% in Marvdasht and Roshan cultivars, respectively. Noticeable effect was detected in case of consortium treatment, suggesting that plant growth promoting rhizobacteria acted synergistically with plant growth promoting endophytes. Finally, our study highlights the importance of co-inoculation with rhizospheric and endophytic bacterial inoculant in improving P efficiency of wheat cultivars.

Fenugreek ( Trigonella foenum-graecum L.) is an annual leguminous crop, widely cultivated as a medicinal plant, a high quality forage crop, or a nitrogen (N) fixing cover crop around the world. There is a lack of information about the effect of irrigation and fertilization on growth and yield of this crop, especially in regions with limited water availability. In this study, we evaluated the effects of moderate ( I 75 : 25% saving in irrigation water) and severe deficit irrigation ( I 50 : 50% saving in irrigation water) regimes on forage, seed, and trigonelin yield of fenugreek in a semi-arid environment (Karaj, Iran). We also examined if application of bio-fertilizers (seed inoculation with Azotobacter chroococcum and Peudomoance fluorescence ) could substitute the need for chemical N, phosphorus (P), and potassium (K) fertilizer in whole or in part. The field experiment was conducted in 2012 and 2013 in a split plot arrangement based on a randomized complete block design with three replications. Forage yield, seed yield, and trigonelline concentration were significantly influenced by deficit irrigation. Implementation of I 75 and I 50 resulted in 40 and 65% lower forage yield compared with full irrigation ( I 100 ). Averaged over fertilizer treatments and two years, fenugreek seed yield in I 100 was 839 kg ha −1 which declined by 27 and 42% under I 75 and I 50 treatments, respectively. Accumulation of trigonelline in fenugreek seeds was elevated from 2.9 g kg −1 in I 100 to 3.1 g kg −1 in I 50 . Fenugreek forage and seed yield, both were significantly improved when integrated fertilizers (biofertilizer + chemical fertilizer) were applied. Among the biological, chemical and integrated fertilizers, fenugreek forage and seed yield best responded to bio + 50% chemical fertilizer. The advantage of the integrated fertilizer over chemical fertilizer was even more pronounced when deficit irrigation was practiced. Fertilization had no significant effect on trigonelline concentration According to the results of this study, integration of biofertilizer + 50% chemical fertilizer could be successfully used for fenugreek production in this region toward minimizing the consumption of chemical fertilizers and improving fenugreek yield, especially under deficit irrigation regimes.

This study evaluated the effects of biochar application on some properties of an alkaline soil and on lentil (Lens culinaris Medik) growth. Lentils were grown in the soil amended with the rates of 0.4, 0.8, 1.6, 2.4, and 3.3 weight percent of two biochars (B 1 and B 2 ), produced from rice husk under different pyrolysis conditions. Lentils were harvested after 70 days. Soil samples were also analysed for changes in physico-chemical properties. The results in dicated that biochar application significantly increased soil organic carbon, cation exchange capacity, available po tassium and below ground biomass of lentil, while it decreased soil bulk density. The results suggested that biochar application to alkaline soils has benefits to both soil quality and plant growth.

The dissipation and detoxification of nicosulfuron (NS) by Pseudomonas aeruginosa B9 isolated from a cornfield soil was investigated. The fastest decline of NS occurred at 40 µg ml−1 in liquid media with 0.25% glucose plus 0.05% yeast extract (DT50 = 4 days) with a notable pH reduction (pH ˂ 5). Bioassay tests showed considerable phytotoxicity of NS for Cress (Lepidium sativum L.) with 50% shoot growth inhibition (SGI) at 40 µg ml−1. The dissipation of NS (40 µg ml−1) by the B9 isolate reduced the SGI significantly (SGI: up to 45 ± 3%) compared to the non-inoculated media (SGI: up to 58 ± 4%). In soils with the B9 isolate, NS dissipation, especially at 0.3 µg g−1, was faster with a more significant SGI reduction (k = 0.08 ± 0.00 day−1; SGI = 2 ± 1%) compared to non-inoculated samples (k = 0.03 ± 0.00 day−1; SGI = 8 ± 1%). NS initially inhibited soil respiration, microbial biomass carbon, and dehydrogenase activity. The effect was however transient, and these parameters recovered within 10 days, especially in the presence of the isolate. Overall, this study proves Pseudomonas aeruginosa B9 as a suitable candidate for bioremediation of NS in contaminated sites.

Widespread application of non-renewable energy resources such as fossil fuels is limited mainly due to their adverse environmental impacts by increasing the amount of greenhouse gas (GHG) emissions. A solution to limit fossil-fuel pollution is the use of renewable energy resources. In the recent years, microalgae have received considerable attention as a suitable feedstock for biofuel production. Microalgae can grow in various aquatic wastewater media and are able to produce biomass, lipids, and hydrocarbons. Using different types of wastewaters as media for algae cultivation could not only reduce their freshwater footprint but also the costs associated with algae cultivation and biofuel production. This chapter presents an overview on various algal cultivation systems as well as on optimization of algal cultivations, while downstream processes including harvesting and drying of microalgae and lipid extraction systems are also reviewed and discussed. Subsequently, different microalgae biofuel production pathways are presented. Finally, the applications of microalgae in integrated systems, i.e., in wastewater treatment and biodiesel production systems and biofixation of carbon, are scrutinized.

The primary objective of this study was the isolation of low-density polyethylene (LDPE)-degrading microorganisms. Soil samples were obtained from an aged municipal landfill in Tehran, Iran, and enrichment culture procedures were performed using LDPE films and powder. Screening steps were conducted using linear paraffin, liquid ethylene oligomer, and LDPE powder as the sole source of carbon. Two landfill-source isolates, identified as Lysinibacillus xylanilyticus XDB9 (T) strain S7-10F and Aspergillus niger strain F1-16S, were selected as super strains. Photo-oxidation (25 days under ultraviolet [UV] irradiation) was used as a pretreatment of the LDPE samples without pro-oxidant additives. The PE biodegradation process was performed for 56 days in a liquid mineral medium using UV-irradiated pure LDPE films without pro-oxidant additives in the presence of the bacterial isolate, the fungal isolate, and the mixture of the two isolates. The process was monitored by measuring the fungal biomass, the ba...

Iran has many hypersaline environments, both the permanent and seasonal ones. One of the seasonal hypersaline lakes in the central desert zone is Aran-Bidgol Lake in which microbial diversity has not been characterized, thus the potential usage of this microbial community in biotechnology remained unknown. In this study, screening the halophilic hydrolytic enzyme-producing bacteria from different areas of this lake led to isolation of 61 gram-positive and 22 gram-negative moderately halophilic bacteria. These bacterial isolates were shown to produce a wide variety of hydrolytic enzymes including DNase, inulinase, amylase, lipase, pectinase, protease, chitinase, pullulanase, cellulase, and xylanase. The most common enzymes were DNase and inulinase in gram-positive bacteria, lipase in gram-negative bacteria, and pullulanase and cellulase in gram-positive cocci. Interestingly, combined hydrolytic activates were observed in some isolates. According to their phenotypic characteristics and comparative partial 16S rRNA sequence analysis, the moderately halophilic strains belonged to the genera Halobacillus, Thalassobacillus, Bacillus, Salinicoccus, Idiomarina, Salicola, and Halomonas.

The aim of this study was to evaluate the impacts of land leveling on some of soil properties. Land leveling as an effective strategy for paddy land management is one of the most important programs run by the Ministry of Jihad-Agriculture in Guilan province, northern part of Iran. Precise land leveling improves irrigation application, fertilization efficiency, and uniform soil moisture for germination. Also, it increases yields and cultivable lands and reduces delivery losses. Running land-leveling projects, however, leads to such disadvantages as severe soil alteration and consequently disruptions to the soil physical, chemical, and biological properties. Based on statistical analysis, on the one hand land, leveling led to significant increases (P

Cyanobacteria are among the most ubiquitous, ecologically important photo-autotrophs on the Earth. They play important roles in terrestrial environments, especially in arid and semi-arid regions. I...

Studies were carried out on the decolorization of textile azo dyes by newly isolated halophilic and halotolerant bacteria. Among the 27 strains of halophilic and halotolerant bacteria isolated from effluents of textile industries, three showed remarkable ability in decolorizing the widely utilized azo dyes. Phenotypic characterization and phylogenetic analysis based on 16S rDNA sequence comparisons indicate that these strains belonged to the genus Halomonas. The three strains were able to decolorize azo dyes in a wide range of NaCl concentration (up to 20% w/v), temperature (25–40 � C), and pH (5–11) after 4 days of incubation in static culture. They could decolorize the mixture of dyes as well as pure dyes. These strains also readily grew in and decolorized the high concentrations of dye (5000 ppm) and could tolerate up to 10,000 ppm of the dye. UV–Vis analyses before and after decolorization and the colorless bacterial biomass after decolorization suggested that decolorization was due to biodegradation, rather than inactive surface adsorption. Analytical studies based on HPLC showed that the principal decolorization was reduction of the azo bond, followed by cleavage of the reduced bond. � 2006 Elsevier Ltd. All rights reserved.

A number of aerobic species capable of decolorizing some of the dyes in a textile mill effluent were isolated. One of the isolates was able to decolorize Terasil black dye under aerobic conditions in the presence of an exogenous carbon source after 5 days. Glucose or starch (%1 ea) are essential for decolorization but the process proceeds faster in the presence of 0.5% yeast extract. Results of the BOD(5) show that the untreated effluent samples have a low BOD value, whereas treated samples show an initial increase in BOD up to 15 days followed by a decrease after 20 days. FT-IR and GC-MS data also reveal that the initial components in the untreated effluent disappear after 20 days of treatment, confirming biodegradation of the dye. Phytotoxicity tests on the untreated effluent samples using the seeds of Lens orientalis, Triticum aestivum, and Triticum boeoticum indicate that the first one is the most sensitive while the last one is the most resistant. On the other hand the treated effluent allows 90% germination in Triticum boeoticum seeds and 100% germination in the other two.