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In this study, aerobic co-composting of tylosin fermentation dregs (TFDs) and sewage sludge with different adding concentrations of copper (Cu) was investigated to inspect the fate of antibiotic resistance genes (ARGs), metal resistance genes (MRGs) and mobile genetic elements (MGEs). Results showed that two concentrations of Cu did affect not only the abiotic factors but the relative abundances of resistance genes. High concentration of Cu inhibited the metabolic capacity of microbial community and the nitrogen-fixing process while had little effect on the degradation of TYL and TOC. The abundance of ermT, mefA, mphA increased partly attributed to the toxic effects and co-selective pressure from heavy metal reflected by MRGs. There was significant correlation among some environmental factors like pH, bio-Cu, organic matters and ARGs., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Erythromycin fermentation residue (EFR) after spray drying could be reused as a soil amendment. However, the effects of spray-dried EFR on antibiotic resistance genes (ARGs), nitrogen cycling, and microbial community structure in soil are rarely reported. In this study, a pot experiment was conducted by adding spray-dried EFR to soil. For the application of 1.0% spray-dried EFR, the residual erythromycin (ERY) could be rapidly removed with the half-life of 22.2 d; the total relative abundance of ARGs increased at first, but decreased to the initial level of the control group in the end; genes related to ammonium assimilation (glnA, gltB, gltD), ammonification (gdhA, gudB, cynT, cynS, ncd2), denitrification (narI, narG, narH), assimilatory nitrate reduction (nirA, nasA), and dissimilatory nitrate reduction (nirD) were enriched; soil microbial community structure presented temporary variation. Network analysis showed significant negative correlations between ARGs and nitrogen cycling genes. The addition of 6.0% spray-dried EFR resulted in the amplification of ARGs and inhibition of nitrogen cycling. This work provides new insights into the effects of spray-dried EFR on ARGs, nitrogen cycling, and microbial community structure within the fertilized soil. [ABSTRACT FROM AUTHOR]

Though heavy metals are widely reported to induce antibiotic resistance propagation, how antibiotic resistance changes in response to heavy metal abundances remains unclearly. In this study, the tylosin fermentation dregs (TFDs) and swine manure co-composting process amended with two exposure levels of heavy metal Zn were performed. Results showed that the bioavailable Zn contents decreased 2.6-fold averagely, and the removal percentage of total tylosin resistance genes was around 23.5% after the co-composting completed. Furthermore, the tylosin resistance genes and some generic bacteria may exhibited a hormetic-like dose-response with the high-dosage inhibition and low dosage stimulation induced by bioavailable Zn contents during the co-composting process, which represented a beneficial aspect of adaptive responses to harmful environmental stimuli. This study provided a comprehensive understanding and predicted risk assessment for the Zn-contaminate solid wastes deposal and suggested that low levels of Zn or other heavy metals should receive more attention for their potential to the induction of resistance bacteria and propagation of antibiotic resistance genes. [ABSTRACT FROM AUTHOR]

Tylosin fermentation dregs (TFDs) are biosolid waste of antibiotics tylosin production process which contain nutritious components and may be recycled as soil amendments. However, the specific ecological safety of TFDs from the perspective of bacterial resistance in soil microenvironment is not fully explored. In the present study, a series of replicated lab-scale work were performed using the simulated fertilization to gain insight into the potential environmental effects and risks of macrolide antibiotic resistance genes (ARGs) and the soil microbial communities composition via quantitative PCR and 16S rRNA sequencing following the TFDs land application as the soil amendments. The results showed that bio-processes might play an important role in the decomposition of tylosin which degraded above 90% after 20 days in soil. The application of TFDs might induce the development of antibiotic-resistant bacteria, change soil environment and reduce the microbial diversity. Though the abundances of macrolide ARGs exhibited a decreasing trend following the tylosin degradation, other components in TFDs may have a lasting impact on both macrolide ARGs abundance and soil bacterial communities. Thus, this study pointed out the fate of TFDs on soil ecological environment when directly applying into soil, and provide valuable scientific basis for TFDs management. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • ERY degradation in mycelial dreg by heat-activated PS oxidation was investigated. • 99.0% ERY was degraded by 25 g PS/kg EMD under 80 °C within 120 min. • Six intermediate products of ERY through the oxidation process were clarified. • Ere(B), erm(A), and erm(B) were reduced by heat-activated PS oxidation. Abstract Erythromycin mycelial dreg (EMD) is a bio-fermentation residue of the pharmaceutical industry that may be used as a nutrient resource. However, the contaminants present in EMD need to be considered and controlled at an acceptable level prior to utilization. In this study, heat-activated persulfate (PS) oxidation of EMD was developed to degrade the residual erythromycin (ERY) and inactivate the ERY-resistant genes. The effects of temperature, initial PS concentration, and pH on the removal of ERY in EMD were studied. The results revealed that 99.0% ERY was degraded by 25 g PS/kg EMD under 80 °C within 120 min. The apparent rate constant (k app) in the acidic condition was higher than that in the alkaline condition. The contribution of sulfate radical (SO 4 · - ) and hydroxyl radical (HO) on ERY removal in EMD was found to be 36.8% and 29.4%, respectively. Six intermediate products (IPs) of ERY were clarified, and total organic carbon (TOC) was efficiently reduced by 99.4%. Finally, the detected ERY-resistant genes ere(B), erm(A), and erm(B) obviously presented a reduction during the heat-activated PS oxidation process. [ABSTRACT FROM AUTHOR]

• TAP effectively promoted the disintegration and solubilization of SFR. • The high level of residual SPM could be completely eliminated by TAP. • The antibacterial activity of SPM was greatly reduced after TAP treatment. • The Antibiotic resistance genes could be almost inactivated. Spiramycin fermentation residue (SFR) can be managed to recycle organic substances through bioprocesses. However, its rigid matrix structure and high residual antibiotic of spiramycin (SPM) are not conducive to the high efficiency of bioprocesses. The pretreatment of SFR by thermally activated peroxydisulfate (TAP) was first employed for improving its biodegradability by matrix structure disintegration and residual SPM degradation. The results demonstrated that the SFR were efficiently disintegrated to smaller particles. The effective destruction of SFR matrix structure was predicted by the release of carbohydrates and proteins, and was intuitively confirmed by scanning electron microscopy (SEM). The production of dissolved organic matters was clearly enhanced by TAP treatment, but the increment decreased with the increase of PDS dosage due to the mineralization of radicals. The degradation of SPM fitted to first-order kinetics model, and its degradation rate was promoted by increasing PDS dosage, increasing activation temperature and decreasing pH. The degradation pathway of SPM was mainly the separation of sugar groups (mycarose, mycaminose and forosamine) from the lactone ring, and the final oxidation product of SPM that have been identified was predicted to be harmless. The efficient and powerful TAP might be a suitable pretreatment approach for improving the biodegradability of SFR. [ABSTRACT FROM AUTHOR]

• The feasibility of improving the OFR composting by HTPT was investigated. • The antibiotics present in compost were significantly reduced by HTPT. • Characterizations of DOM were conducted to assess the maturity of OFR. • HTPT efficiently shortened the time required for achieving the maturity of OFR. In this study, the feasibility of employing hydrothermal pretreatment (HTPT) to improve the composting of oxytetracycline fermentation residue (OFR) was evaluated by investigating the depletion of oxytetracycline (OTC) and evolution of dissolved organic matter (DOM). HTPT drastically declined the final content of OTC and its main transformation intermediates in OFR compost from 89.96 to 2.61 mg/kg. Although HTPT slightly increased the DOM content and significantly decreased the contents of biodegradable and humified compounds in OFR compost, it did not significantly change the germination index of OFR compost. Nevertheless, the time required for the overall pattern of DOM parameters to reach stabilization was shortened from 28 to 14 days by HTPT. Taken together, although HTPT did not change the maturity degree of OFR compost, it obviously shortened the OFR composting cycle and lowered the potential risk of OFR compost, confirming that HTPT could efficiently improve the OFR composting. [ABSTRACT FROM AUTHOR]

• HT significantly destroyed OFR matrix structure and produced hydrophilic matters. • The high levels of residual oxytetracycline were almost completely removed by HT. • The antibacterial activity was reduced to a negligible level after HT. • It is feasible to improve the biodegradability of OFR by HT. Oxytetracycline fermentation residue (OFR) can be managed by bioprocesses to recycle organic substances. However, the organic materials present are resistant to biodegradation due to protection by the OFR matrix structure, and the high levels of residual oxytetracycline have unavoidably negative impacts on microorganisms in bioprocesses and result in the poor biodegradability of OFR. Hydrothermal treatment (HT) is promising for processing OFR to improve its biodegradability, but there is still insufficient practical experience with HT of OFR. To explore the applicability of employing HT as a pretreatment to improve the biodegradability of OFR, HT processes at temperatures varying from 90 °C to 180 °C were performed on OFR to disintegrate its matrix and inactivate the high levels of residual oxytetracycline. The results demonstrated that performing HT clearly enhanced the production of hydrophilic matter including soluble chemical oxygen demand (SCOD), soluble carbohydrates and soluble proteins. Nevertheless, the drawbacks of HT for degrading soluble organics and mineralizing total organics were clearly observed at 180 °C. Efficient destruction of the OFR matrix structure was speculated based on the release of carbohydrates and proteins and was visually confirmed by photomicrographs and scanning electron microscopy graphs. The disappearance of oxytetracycline fit a pseudo first-order kinetics model and the toxic intermediates of oxytetracycline, including 4-epi-oxytetracycline, α -apo-oxytetracycline and β -apo-oxytetracycline, could not be persistent during HT. Antibacterial activity linked to oxytetracycline greatly decreased after HT. The conditions of 150 °C and 180 min resulted in relatively good results in SCOD release and oxytetracycline inactivation. All these suggest that HT effectively improves the biodegradability of OFR. [ABSTRACT FROM AUTHOR]

• Hydrothermal pretreatment obviously affected bacterial diversity and composition. • ARGs inevitably elevated during the composting process of OFR. • Hydrothermal pretreatment efficiently reduced the enrichment of ARGs. Hydrothermal pretreatment can efficiently remove the residual antibiotics in oxytetracycline fermentation residue (OFR), but its effect on antibiotic resistance genes (ARGs) during composting remains unclear. This study compared the shifts in bacterial community and evolutions in ARGs and integrons during different composting processes of OFRs with and without hydrothermal pretreatment. The results demonstrated that hydrothermal pretreatment increased the bacterial alpha diversity at the initial phase, and increased the relative abundances of Proteobacteria and Actinobacteria but decreased that of Bacteroidetes at the final phase by inactivating mycelia and removing residual oxytetracycline. Composting process inevitably elevated the abundance and relative abundance of ARGs. However, the increase in ARGs was significantly reduced by hydrothermal pretreatment, because the removal of oxytetracycline decreased their potential host bacteria and inhibited their horizontal gene transfer. The results demonstrated that hydrothermal pretreatment is an efficient strategy to reduce the enrichment of ARGs during the OFR composting. [ABSTRACT FROM AUTHOR]

• Hydrothermal treatment (HT) is effective to remove residual erythromycin and ARGs. • The hydrolysate exists certain antimicrobial activity against S. aureus. • HT enhanced the release of the protein-like polymers for bioenergy recycling. • The obtained solid products have the higher heating value of approx. 20 MJ/kg. • Hydrothermal technology was proved effective to recycle and harmlessly dispose EFR. Erythromycin fermentation residue (EFR) is a byproduct of bio-fermentation process for producing erythromycin, representing both an economic and environmental burden for the pharmaceutical industry. While hydrothermal treatment (HT) can solve the pollution and toxic problems, the impacts of HT on harmless performance and the bioresource properties of the complex EFR matrix remain unclear. In this study, the abatement of residual erythromycin, its associated antibiotic resistance genes and antimicrobial activity were investigated to evaluate the harmless performance of HT for EFR, and the feasibility of recycling hydrolysates as bioenergy was also assessed. The results showed that raising HT temperature significantly improved the harmless performance. The removal rate of residual erythromycin in EFR reached over 88% and the total absolute abundance of erythromycin resistance genes decreased by more than 3 logs with HT at 160°C for 60 min, but the hydrolysates still existed specific antimicrobial activity against S. aureus.. Additionally, the HT temperature remarkably influenced the bioresource properties of EFR-hydrolyzed products. The release of the protein-like polymers into the liquid phase was enhanced, while high HT temperature worsened the nutrient substances. The elevated drying property of solid products from EFR was observed along with the higher heating value of around 20 MJ/kg, indicating a potential of recycling solid products as biofuel. Total energy production from biogas conversion and biofuel incineration treating 1.0 kg raw EFR was 1875 kJ. Hydrothermal technology was proved to realize the harmless treatment of EFR and meanwhile to be promising for recycling EFR as bioenergy. [ABSTRACT FROM AUTHOR]

Cephalosporin fermentation residue (CFR) is a byproduct of the pharmaceutical industry that may be disposed through land application. While this organic residue can improve soil physico-chemical properties, the possibility of CFR-induced antibiotic resistance in the native soil microbial community still needs to be investigated. In a lab-based incubation study, the CFR-induced selection for antibiotic resistance genes (ARGs), including changes in the structure of native soil bacterial populations, antibiotic-induced selection and lateral transfer potential, was determined with quantitative PCR array and 16S amplicon sequencing. CFR amendment of soil increased the abundance of β-lactam resistance genes over time. There were higher abundance of β-lactam resistance genes in soil receiving raw CFR than treated CFR, indicating that antibiotics or metabolites contained in raw CFR contributed to the selection of resistant microorganisms. There were more mobile genetic elements in the raw CFR-amended soil, which is further evidence that bacterial responses contributed to the dissemination of antibiotic resistance genes within species in the bacterial community. Marked shifts in the native soil bacterial community composition were observed and several specific genera probably contributed to the resistance as representatives of corresponding phyla Bacteroidetes, Actinobacteria, Proteobacteria and Firmicutes, suggesting a phylogenetic basis for the increase of resistance genes in CFR-amended soil. These results imply the selection for β-lactam resistance genes at multiple levels following the application of CFR to arable soil. • Cephalosporin fermentation residue (CFR) may be disposed as a soil amendment. • CFR-induced antibiotic resistance in soil microbial community was investigated. • CFR amendment enhanced the β-lactam resistance and horizontal gene transfer potential. • Marked shifts in the native soil bacterial community composition were observed. • A multiple selection explained for the increase in soil resistance genes. [ABSTRACT FROM AUTHOR]

Lipstatin fermentation residue (LFR) is a byproduct of the pharmaceutical industry that may be disposed through land application after composting due to its high organic matter content. The effect of composted LFR application on the soil properties and microbial community still needs to be investigated before field application to verify its suitability and safety. Over a three months laboratory soil incubation experiment, the impacts of composted and raw LFR on soil properties, enzyme activities and bacterial community were investigated. The results indicated that the pH value of the soil fertilized with composted LFR decreased slightly, but the EC value increased significantly. It was worth noting that there was no measurable accumulation of lipstatin with LFR fertilization. The soil nutrients including available phosphorus, available potassium, organic matter and soluble organic matter were significantly increased in composted LFR-fertilized soil. In addition, the culturable microorganisms and enzymes were not inhibited throughout the incubation of composted LFR in soil. The composted LFR improved the soil fertility, environment and microbial biomass, which demonstrated its potential as a fertilizer. This study will provide a theoretical basis for the resource utilization of LFR. [Display omitted] • Composted LFR was utilized as organic fertilizer with high efficacy. • SOM content increased after the application of composted LFR. • The introduced lipstatin completely degraded within 30 d. • Composted LFR did not cause significant changes to soil bacterial community. [ABSTRACT FROM AUTHOR]

[Display omitted] • TAP pretreatment significantly increased cumulative CO 2 and NH 3 emissions. • TAP pretreatment decreased cumulative CH 4 and N 2 O emissions. • The maturity of SFR compost promoted by TAP pretreatment. • The enrichment of maturity attributed to the increase of HA and NO 3 –. Aerobic composting combined with appropriate pretreatment is promising to achieve the utilization of antibiotics fermentation residues (AFRs). This research studied the effect of thermally activated peroxodisulfate (TAP) pretreatment on greenhouse gas (GHGs) emission, dissolved organic matter (DOM) and maturity evaluation during spiramycin fermentation residue (SFR) composting. Three treatments were conducted from co-composting of SFR and wheat straw, while 90% and 99.9% residual spirmycin removal pretreatment SFR by TAP were provided and compared with raw SFR. The cumulative CO 2 and NH 3 emissions increased by 17.2% and 30.8% after TAP pretreatment removed 99.9% residual spiramycin in SFR, while the cumulative CH 4 and N 2 O emission decreased by 34.0% and 5.27%, respectively. The DOM, humic acid (HA)/fulvic acid (FA) and NH 4 +/NO 3 – analysis confirmed that the composting maturity was improved with the increasing of HA and NO 3 – content by TAP pretreatment. [ABSTRACT FROM AUTHOR]

[Display omitted] • Kanamycin was removed (>99.0 %) via tea polyphenols supplemented for the first time. • pH effected mostly in comparison of MnO 2 dosage and temperature from RSM results. • The antimicrobial activity of the mixture decreased greatly after reaction (>27). • Kanamycin was mainly removed by being transferred to humic-like acid (HLA) product. • The new approach could be applied in actual waste to remove kanamycin (>99.0 %). Kanamycin, a typical aminoglycoside antibiotic, is mainly used for the treatment of diseases in humans or animals, while the related antibiotic pollution has been regarded as a serious issue. In this study, a green novel approach to remove kanamycin was established, specifically, kanamycin was specifically removed through abiotic humification process with tea polyphenols (TPs) as the polyphenol donor. The results demonstrated that the kanamycin could be effectively removed by TPs under alkaline conditions, with a 99.9 % highest removal efficiency. Among the three factors (pH, temperature and MnO 2 dosage) selected in this study, pH was the most critical factor, with an increase in reaction pH (>6.0) leading to a higher kanamycin removal efficiency, and the temperature and MnO 2 dosage ranked as the second and third important factor. Furthermore, kanamycin was mainly removed by being transformed into humic-like acid (HLA) product, and the product antimicrobial activity could be significantly reduced (≥27). Finally, satisfying removal efficiency of kanamycin were observed during the application of TPs in kanamycin fermentation wastewater and kanamycin mycelial residue (KMR), with the highest kanamycin removal efficiency was 99.9 %, and 99.6 %, respectively. This study could also offer insights for the removal of other pollutants containing primary amine or polyphenols. [ABSTRACT FROM AUTHOR]

To reduce the adverse effects of antibiotics and antibiotic resistance genes (ARGs) in the environment, nitrogen-doped biochar (NLBH), derived from lincomycin fermentation dregs (LFD), was employed as an activator in a persulfate (PDS) oxidation system. The system was evaluated for its ability to degrade tetracycline (TC), inactivate antibiotic resistant bacteria (ARB) and remove ARGs. The degradation efficiency of TC in the NLBH/PDS system (70.1%) was higher than that in the pristine biochar/PDS system (10.3%). It was confirmed that the defects and edge pyridinic nitrogen generated in the nitrogen doping process were the reactive sites for PDS activation. According to electron paramagnetic resonance (EPR) and radical quenching experiments, the major mechanism for PDS activation was a non-radical pathway dominated by singlet oxygen (1O 2). Radical pathways involving sulfate (SO 4 ·-) and hydroxyl radicals (·OH) were also at play in the NLBH/PDS system, but their role was minor. TC was principally degraded by hydroxylation, demethylation, and decarboxylation, and within 90 min, the NLBH/PDS system effectively inactivated 71.5% of ARB (Pseudomonas sp. HLS-6). Intracellular ARGs (iARGs; sul 1, sul 2) and intI 1 had log reduction efficiencies of 2.73–4.04 and 2.70, respectively, whereas, extracellular ARGs (sul 1 and sul 2) and intI 1 accumulated noticeably by 1.52–4.18-and 4.92-log, respectively. This work highlights a promising alternative technique for the removal of antibiotics, ARB and iARGs in future advanced wastewater treatment systems. [Display omitted] • N-doped biochar exhibited excellent performance for PDS activation. • Pyridinic N and defects in N-doped biochar might be the essential catalytic sites. • Nonradical pathway involved 1O 2 makes major contribution on pollutants removal. • More than 70% of TC and ARBs were degraded and inactivated in reaction system. • A 4.04-log reduction of iARGs was achieved in N-doped biochar/PDS system. [ABSTRACT FROM AUTHOR]

• Differential responses of iARGs and eARGs to THP + fermentation was revealed. • THP reduced the absolute abundance of iARGs but resulted in the release of eARGs. • Log removal of total ARGs in sludge fermentation was not impacted by THP. • Functional bacterial phylogeny was the driver in shaping intracellular ARGs. • eARGs degraded rather than propagated through transformation in fermented sludge. Thermal hydrolysis pretreatment (THP) can effectively remove the antibiotic resistance genes (ARGs) from sewage sludge, but the rebounding effects in the subsequent anaerobic fermentation are often observed. The purpose of this study was to elucidate the distribution and fate of intracellular and extracellular ARGs (iARGs and eARGs) in the sludge acidogenic fermentation process coupled with THP. Our results revealed that THP significantly reduced the absolute abundance of total ARGs in raw sludge but increased eARGs by 0.3–1.4 log units under practical conditions (140 °C for 30 min). There is no significant difference in the removal of total ARGs between the two acidogenic fermenters receiving raw and hydrolyzed sludge, with iARGs prevailing in the produced biosolids. The succession of bacterial community and the co-occurrence relationships among ARG type, mobile genetic elements and bacterial taxa were observed, suggesting a phylogenetic basis for the iARGs patterns in fermented sludge. However, eARGs were susceptible to biodegradation with a half-life of 2.34 h and they contributed limitedly to the ARGs propagation through transformation. These findings suggest an emphasis on the mitigation of iARGs during the acidogenic fermentation of sludge, which would be achieved by lowering the richness and physicochemical destruction of potential hosts. [Display omitted] [ABSTRACT FROM AUTHOR]