•Biochar as an amendment for composting.•Ammonia emission and nitrogen loss reduced by amending sewage sludge and wood chips mixtures with biochar.•Increased temperatures and longer thermophilic ...phase during composting of mixtures with biochar addition.
The presented research included laboratory scale composting of sewage sludge and woodchips mixtures amended with biochar in 45L reactor system conducted for 16 days. The effect of biochar amendment on ammonia emission was investigated. The addition of biochar reduced significantly volatilization of ammonia during the first week of the process. Also, the addition of biochar increased temperature and organic matter decomposition.
Summary
Actinobacteria are producers of a plethora of natural products of agricultural, biotechnological and clinical importance. In an era where mankind has to deal with rapidly spreading ...antimicrobial resistance, streptomycetes are of particular importance as producers of half of all antibiotics used in the clinic. Genome sequencing efforts revealed that their capacity as antibiotic producers has been underestimated, in particular as many biosynthetic pathways are silent under standard laboratory conditions. Here we review the global regulatory networks that control antibiotic production in streptomycetes, with emphasis on carbon‐ and aminosugar‐related nutrient sensory pathways. Recent research has revealed intriguing connections between these regulons, and overlap and antagonism between the activities of among others the global regulatory proteins AtrA, DasR and Rok7B7 as well as GlnR (nitrogen control) and PhoP (phosphate control), are discussed. Finally, we provide ideas as to how these novel insights might help us to find ways to activate the transcription of silent biosynthetic gene clusters.
Streptomycetes are prolific producers of antibiotics and other natural products, but many biosynthetic gene clusters are silent under standard laboratory conditions. In this review, we look into the global nutrient sensory networks that control antibiotic biosynthetic pathways in Streptomyces, and highlight cross‐talk between different pleiotropic regulators. Approaches to harness this information to activate the production of silent antibiotics are discussed.
Streptomycetes produce a wealth of natural products, including over half of all known antibiotics. It was previously demonstrated that N-acetylglucosamine and secondary metabolism are closely ...entwined in streptomycetes. Here we show that DNA recognition by the N-acetylglucosamine-responsive regulator DasR is growth-phase dependent, and that DasR can bind to sites in the S. coelicolor genome that have no obvious resemblance to previously identified DasR-responsive elements. Thus, the regulon of DasR extends well beyond what was previously predicted and includes a large number of genes with functions far removed from N-acetylglucosamine metabolism, such as genes for small RNAs and DNA transposases. Conversely, the DasR regulon during vegetative growth largely correlates to the presence of canonical DasR-responsive elements. The changes in DasR binding in vivo following N-acetylglucosamine induction were studied in detail and a possible molecular mechanism by which the influence of DasR is extended is discussed. Discussion of DasR binding was further informed by a parallel transcriptome analysis of the respective cultures. Evidence is provided that DasR binds directly to the promoters of all genes encoding pathway-specific regulators of antibiotic production in S. coelicolor, thereby providing an exquisitely simple link between nutritional control and secondary metabolism.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
•Biochar as an amendment for sewage sludge mixtures prior to vermicomposting.•Biochar as a source of micro and macronutrients to the earthworms.•Precomposted sewage sludge mixture amended with ...biochar as a growing medium for earthworms.•Biochar to support the growth and reproduction of earthworms.•Increased reproduction rate of the earthworms in the precomposted mixtures with higher biochar ratio.
The obtained results showed that the addition of biochar to the mixture of sewage sludge and wheat straw prior to composting facilitated the growth and reproduction of Eisenia fetida during laboratory vermicomposting of this mixture. After 4 weeks of vermicomposting the average number of produced cocoons in the mixtures amended with biochar increased by 13% for SS+ST+4%B and 66% for SS+ST+8%B. Also, the number of juvenile earthworms was higher in the mixtures amended with biochar. However, the total weight of earthworms declined with the depletion of organic matter after 18 weeks of the experiment. Amending sewage sludge mixtures with biochar for vermicomposting resulted in higher reproduction rates, and thus could allow faster and more efficient conversion of sewage sludge into vermicompost.
The present study evaluated the performance of microalgae Chlorella vulgaris in an Enterobacter sp. MN17-assisted textile industry wastewater treatment system for decolorization, removal of heavy ...metals (Cu, Cr, Pb, and Cd), and chemical oxygen demand (COD). Different dilutions (5, 10, and 20%) of wastewater were prepared to decrease the pollutant toxicity for culturing microalgae and bacteria. Reduction of color, COD, and metal contents by microalgal treatment of wastewater varied greatly, while removal efficiency (RE) was significantly enhanced when endophytic bacterial strain MN17 inoculum was applied. Most notable, results were found at a 5% dilution level by Enterobacter sp. MN17-inoculated C. vulgaris medium, as chromium (Cr), cadmium (Cd), copper (Cu), and lead (Pb) concentrations were decreased from 1.32 to 0.27 mg L−1 (79% decrease), 0.79–0.14 mg L−1 (93% decrease), 1.33–0.36 mg L−1 (72% decrease), and 1.2–0.25 mg L−1 (79% decrease), respectively. The values of COD and color were also significantly decreased by 74% and 70%, respectively, by a C. vulgaris–Enterobacter sp. MN17 consortium. The present investigation revealed that bacterial inoculation of microalgae significantly enhanced the removal of coloring agents and heavy metals from textile wastewater by stimulating the growth of algal biomass. This study manifested the usefulness of microalgae–bacterial mutualism for the remediation of heavy metals, COD, and color in industrial effluents. Microalgae consortia with growth promoting bacteria could be a breakthrough for better bioremediation and bioprocess economy. Thus, further studies are needed for successful integration of microalgae–plant growth promoting bacterial (PGPB) consortium for wastewater treatments.
The global transcriptional regulator DasR connects N-acetylglucosamine (GlcNAc) utilization to the onset of morphological and chemical differentiation in the model actinomycete Streptomyces ...coelicolor. Previous work revealed that glucosamine-6-phosphate (GlcN-6P) acts as an allosteric effector which disables binding by DasR to its operator sites (called dre, for DasR responsive element) and allows derepression of DasR-controlled/GlcNAc-dependent genes. To unveil the mechanism by which DasR controls S. coelicolor development, we performed a series of electromobility shift assays with histidine-tagged DasR protein, which suggested that N-acetylglucosamine-6-phosphate (GlcNAc-6P) could also inhibit the formation of DasR-dre complexes and perhaps even more efficiently than GlcN-6P. The possibility that GlcNAc-6P is indeed an efficient allosteric effector of DasR was further confirmed by the high and constitutive activity of the DasR-repressed nagKA promoter in the nagA mutant, which lacks GlcNAc-6P deaminase activity and therefore accumulates GlcNAc-6P. In addition, we also observed that high concentrations of organic or inorganic phosphate enhanced binding of DasR to its recognition site, suggesting that the metabolic status of the cell could determine the selectivity of DasR in vivo, and hence its effect on the expression of its regulon.
•Earlier works showed that GlcN-6P is an allosteric effector of DasR in S. coelicolor.•EMSAs suggest that GlcNAc-6P could prevent more efficiently DasR binding to DNA.•Inactivation of nagA results in constitutive activity of a DasR-repressed promoter.•Inorganic and organic phosphate improves DasR-binding to DNA.•The metabolic status of the cell could determine the selectivity of DasR-binding.
•Treated waste water positively influence mango yield.•Salicylic acid influences the impact of treated waste water on Mango.•Mango cv. “Keitt” possess better protection mechanisms against oxidative ...damage as compared to cv. “Ewais”.
Limitation of fresh water for agriculture irrigation is a worldwide problem, especially in countries located in the arid region like Egypt. This work demonstrates the impact of treated wastewater on two mango cultivars, cv. “Keitt” and cv. “Ewais”. Treated wastewater contains comparatively more contaminant than fresh water, therefore salicylic acid (SA) was added to the treated wastewater to study their combined impact on mango cultivars. Observation indicated that both cultivars positively responded to treated wastewater and/or SA in a similar manner regarding growth, yield and fruit quality parameters. Obtained data revealed that treated wastewater and/or SA promoted vegetative growth and exhibited inhibitory role on the occurrence of malformation and fruitlet abscission. Studied biochemical features related to lipid peroxidation and oxidative system were differently affected. Cultivar “Keitt” had higher activity of catalase, peroxidase, and superoxide dismutase. as compared to cv. “Ewais”. In the resistant cv. “Keitt” the constitutive level of lipid peroxidation was lower, but the activity of enzymatic antioxidants and non-enzymatic antioxidants was higher than the susceptible cultivar “Ewais”. Similarly, Nitrogen metabolism enzymes and photosynthetic performance were inherently higher in cv. “Keitt”. The comparative analysis between the two mango cultivars, based on malformation percentage analysis, indicated that cv. “Keitt” can be categorized into the tolerant group (1–10%), whereas cv. “Ewais” into susceptible ones (20–40%). Our results suggested that cv. “Keitt” possess better protection mechanisms against oxidative damage as compared to the relatively susceptible cultivar “Ewais”. It is based on maintaining higher inherited and increased activity of the antioxidant system. Our work underlines the relation between malformation tolerance and antioxidant defence system. In this work, we suggest the performance of antioxidant defence system as a potential biochemical indicator for screening mango genotypes for malformation behaviour.
Beet molasses vinasse is formed in large quantities as a waste product of the distillery industry, where the molasses derived from sugar beet is used as a raw material. This vinasse has a dark color, ...low pH, and chelating properties. Many microorganisms have the ability to decolorize and biodegrade beet molasses vinasse. In this work, different cultivation parameters (the type of the bacterial culture; static or agitated) and medium components ((NH
4
)
2
SO
4
, KH
2
PO
4
, yeast extract, glucose, and peptone, and the vinasse concentration) were evaluated utilizing Plackett-Burman design to identify the important factors influencing the vinasse decolorization by Bacillus megaterium ATCC 14581. The significant variables were selected as follows: (NH
4
)
2
SO
4
, KH
2
PO
4
, glucose, and the concentration of vinasse. These four factors should be chosen as being promising for further optimization studies. The maximum color removal was 38%.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
PDF
