The wastewater containing petroleum hydrocarbons is mainly produced in the process of petroleum exploitation and petroleum products processing. It encompasses the water polluted by leakage in oil exploitation, the wastewater produced in machining, and the wastewater produced using auxiliaries in leather printing and dyeing. The wastewater containing petroleum hydrocarbons has high organic matter content, high toxicity, and poor biodegradability. Biodegradation has become one of the main research hotspots of the treatment of wastewater containing petroleum hydrocarbons because of no secondary pollution. Based on the latest literature and our research results, this paper details the composition of wastewater containing petroleum hydrocarbon, microbial species for biodegradation, biodegradation mechanism, biochar immobilization and remediation technology, and degradation genes and enzymes. This paper can provide reference for the further study of microbial flora degradation of wastewater containing petroleum hydrocarbon.

[Objective] To obtain the enriched groups of target microorganisms from the natural environment of the study area and establish the pure culture, improve the key link of the basic research on bio-geochemistry in methane leakage areas, and provide ideas and references for the enrichment and culture of other unknown microorganisms. [Methods] Microorganisms in marine sediments from methane leakage areas were isolated and cultured, and a sound experimental methodology for marine microorganisms was refined, including on-site treatment of microbial samples, preparation and sterilization of anaerobic culture media, and enrichment, culture, and isolation of microorganisms. High-throughput sequencing of microorganisms was conducted for gene sequencing and microbial identification, and different experimental conditions and experimental cycles were designed for in vivo microbial culture experiments. The short-term experiment (1.5 d) was conducted with the single factor method to study the effects of environmental factors (light, medium concentration, temperature, and pH) on microorganisms. The medium-term experiment (22 d) verified the results of the short-term experiment and determined the more suitable culture conditions. The long-term experiment (more than 250 d) was carried out to further study the growth status and activity of enriched microbial groups under specific conditions by real-time quantitative tracking of microorganisms. [Results] In the short-term culture, the activity of anaerobic sludge microbial suspension significantly increased under natural light (reached the peak at the time point of 17 h, with the iron concentration of 16.7 mg/L, four times the initial value), while the buffer period was prolonged in the dark environment (0-15 h). The activity of marine sediment microbial suspension was better in the dark environment (with high values at time points of 14 h/35 h), and the activity in the acid/base environment (pH 5.0/9.0) was higher than that in the neutral environment (iron concentrations of 4.3 mg/L vs. 11.1 mg/L, respectively). In the medium-term culture, the activity of anaerobic sludge microbial suspension was stable under 4 ℃ and acid conditions (with the decrease of only 20% in iron concentration), while the marine sediment microbial suspension preferred higher temperature and alkaline environment (with the activity increased after adaptation to pH 9.0). The global analysis showed that the first 15 days were the temperature adaptation period, and then temperature became the key regulatory factor. In the long-term culture, the activity of anaerobic sludge microbial suspension fluctuated periodically (first decreasing and then increasing after change of the culture medium every 50 days), while it declined irreversibly after 150 d. The marine sediment microbial suspension showed strong adaptability (with the activity peaked on days 117-145 under high pressure and the estimated doubling cycle of about 130 d) and maintained serrated stable activity under room pressure (iron concentration of 3.0-10.4 mg/L). [Conclusion] Anaerobic sludge microorganisms are sensitive to light and medium concentration. Their activity is improved by short-term light but inhibited by long-term light. Dark environment and 100% concentration medium are more suitable for growth of anaerobic sludge microorganisms (4 ℃, acidic environment, doubling cycle of 15 d). However, marine sediment microorganisms under the dark+100% medium and high temperature+alkaline environment conditions demonstrate stronger adaptability. Although their short-term activity is less affected by light, it takes about 130 days to double, and the adaptability to the high pressure environment significantly affects the growth process.

[Objective] To study the mechanisms of mutual promotion between chemolithoauto-trophic sulfur-oxidizing bacteria and chemoheterotrophic bacteria under co-culture based on carbon metabolism. [Methods] Ion chromatography was employed to determine the concentrations of S₂O₃^2‒ (thiosulfate) and SO₄^2‒ (sulfate). Bacterial growth dynamics were monitored by the dilution plate method. Extracellular carbon characteristics were analyzed via total organic carbon analyzer measurement and LC-MS. Cellular morphology was observed by scanning electron microscopy. The relative mRNA levels of related genes were quantified by RT-qPCR. [Results] During the growth process, sulfur-oxidizing bacteria continuously fixed inorganic carbon and secreted organics, providing a stable carbon source for the growth of heterotrophic bacterium. In return, heterotrophic bacteria significantly enhanced the sulfur-oxidizing and carbon-fixing capabilities of sulfur-oxidizing bacteria. This was evidenced by the significantly up-regulated expression of the enzyme gene soxB involved in sulfur oxidation and the RubisCO gene cbbL involved in carbon fixation. Additionally, the production of extracellular polymeric substances was induced, which enhanced the biofilm formation. [Conclusion] This study elucidated the interaction mechanisms between sulfur-oxidizing bacteria and heterotrophic bacteria, particularly the significant enhancement of the carbon-fixing capability of sulfur-oxidizing bacteria. The findings provide a new perspective for the enrichment culture of chemolithoautotrophic bacteria and for understanding the carbon fixation mechanisms of autotrophic sulfur-oxidizing bacteria in microbial communities. Additionally, this study offers theoretical support for the low-carbon and efficient treatment of wastewater.

Coastal wetlands, among the most productive ecosystems on Earth, are situated at the interface between land and ocean, receiving substantial nitrogen inputs. These ecosystems exhibit active nitrogen cycling and play a crucial role in global nitrogen budgets and climate regulation. Archaea constitute a critical component of the microbial communities in coastal wetlands, yet their ecological significance was overlooked. The advancements in novel biological technologies have unveiled the diversity and ecological functions of archaea, highlighting their significant contributions to nitrogen cycling. This review summarizes the distribution and diversity of archaea in coastal wetland ecosystems, with a particular focus on their roles in key nitrogen cycling processes such as nitrogen fixation, nitrification, denitrification, and nitrate ammonification. In addition, for the application of archaea in global climate change mitigation, we explore the idea of using archaeal communities to reduce nitrous oxide emissions from coastal wetlands.

[Objective] To compare the bacterial diversity and community composition between the rhizosphere and non-rhizosphere soil of Gynostemma longipes in different planting regions and reveal the key environmental factors by correlating the bacterial community composition with soil physicochemical properties. The findings are expected to provide a reference for the cultivation and introduction of this plant and lay a basis for exploring the relationship between rhizosphere microorganisms and the chemical component content of G. longipes in different planting regions. [Methods] High-throughput sequencing and soil physicochemical property measurement were employed to compare the bacterial diversity and community composition of G. longipes in different planting regions and reveal the key environmental factors influencing the bacterial community. [Results] A total of 97 085 bacterial amplicon sequence variants (ASVs) were obtained. The bacterial community composition in G. longipes soil showed significant differences among different planting regions (R=0.562, P=0.001) but no significant differences between rhizosphere and non-rhizosphere soil. Proteobacteria (27.40%‒36.67%) and Acidobacteriota (15.60%‒22.19%) were the dominant bacterial phyla. Soil pH, available phosphorus, available potassium, soil organic matter, and alkali-hydrolyzable nitrogen were identified as key environmental factors influencing the bacterial community composition in G. longipes soil. [Conclusion] Based on the sample analysis in this study, the bacterial community diversity and composition of G. longipes varied significantly aross different locations and were closely associated with soil physicochemical properties. This study provides a reference for the cultivation and introduction of G. longipes and gives insights into the relationship between soil microorganisms and secondary metabolite accumulation of G. longipes.

In marine aquaculture, the accumulation of antibiotics such as sulfamethoxazole (SMX) has contributed to the spread of antibiotic-resistant bacteria and genes, posing a serious threat to ecological health. Biological treatment of antibiotic-contaminated wastewater is an essential approach to mitigate these environmental risks. [Objective] To isolate a salt-tolerant strain LS-1 with high SMX degradation efficiency from the sediment of an inshore aquaculture pond, examine the effects of environmental factors on the degradation capacity of this strain, optimize the SMX degradation conditions, elucidate the degradation pathway through product analysis, and evaluate the toxicity of the degradation products. [Methods] The isolated strain was identified by 16S rRNA gene sequencing and phylogenetic analysis. Single factor experiments and response surface methodology were employed to optimize the degradation conditions. GC-MS and the luminescent bacteria test for acute toxicity were adopted to analyze the degradation products and their toxicity. [Results] Strain LS-1 showed 99.79% sequence similarity with Alcaligenes aquatilis strain AS1. Tryptone was determined to be the optimal exogenous carbon source for both growth and SMX degradation. The strain exhibited robust growth across a temperature range of 20‒35 ℃, salinities of 15‰‒35‰, SMX concentrations from 10 to 100 mg/L, and pH 7.0‒9.0. Response surface analysis revealed that SMX concentration, initial pH, and temperature significantly influenced the SMX degradation rate, in descending order of importance. Under optimal conditions (SMX concentration of 33 mg/L, pH 7.4, and 30 ℃), the strain achieved a maximum degradation rate of 60.17% within 48 h. MS results indicated that LS-1 degraded SMX via acetylation and hydroxylation pathways. The results of the luminescent bacteria test for acute toxicity demonstrated a progressive reduction in biological toxicity during the SMX degradation process. [Conclusion] The SMX-degrading strain LS-1 can effectively adapt to marine environmental conditions, reducing SMX-induced toxicity in water. This study highlights the potential of LS-1 for controlling antibiotic pollution in marine aquaculture wastewater.

[Objective] To study changes of the bacterial community structure in the Second Drainage Ditch in Ningxia after ecological engineering. [Methods] We employed high-throughput sequencing to study the bacterial community structures in water samples. We explored the factors affecting the bacterial community structure by non-metric multidimensional scaling (NMDS) and redundancy analysis (RDA). [Results] From August 2021 to August 2022, the ammonium nitrogen, total nitrogen (TN), permanganate index, dichromate oxidizability (COD_Cr), and fluoride in the water decreased substantially after the ecological engineering. The dominant bacterial phyla in the water were Proteobacteria, Actinobacteria, Bacteroidetes, and Chloroflexi and the dominant genera included hgcI_clade, SAR11_cladeIII, Limnohabitans, Rhodoferax, and Flavobacterium. The bacterial community structures showed significant differences across different sampling locations. The NMDS results revealed significant variations in the bacterial community structure across different sampling months. The RDA results indicated that total phosphorus (TP), COD_Cr, and pH were the key factors influencing the bacterial community structure. Notably, TP, COD_Cr, and TN together explained the largest variance (8.81%) in the bacterial community structure, followed by TP combined with COD_Cr (-8.05%). [Conclusion] After ecological engineering, the water quality of the Second Drainage Ditch improved, and the bacterial community structure became more diverse. The physicochemical properties of the water strongly influence the distribution and diversity of bacterial communities in the Second Drainage Ditch in Ningxia, which provide a scientific basis for managing the regional water environment.

Microbial communities in aquatic sediments are highly sensitive to environmental changes and serve as key indicators for assessing ecosystem health. As an emerging ecological remediation material, calcium peroxide (CaO₂) has showcased increasing application in the treatment of aquatic sediments, and its impact on microbial communities has become a frontier topic in ecological research. This review fucoses on the influencing mechanisms of CaO₂ on microbial communities in aquatic sediments from the perspective of microbial ecology. CaO₂ exerts multidimensional effects on the structures and functions of microbial communities by significantly altering the redox environment of the sediments. Regarding the community diversity, CaO₂ substantially enhances the alpha-diversity and species richness of microbial communities. In terms of the community composition, CaO₂ promotes the proliferation of functional genera such as Nitrosomonas and Thiobacillus, which possess ammonia-oxidizing and sulfur-oxidizing capabilities, respectively, while suppressing the growth of anaerobic fermenters (e.g., Clostridium) and sulfate reducers (e.g., Desulfovibrio). This function-oriented control mechanism indicates that CaO₂ selectively enriches microbial groups that facilitate nitrogen and sulfur cycling, while inhibiting the proliferation of anaerobic taxa that produce harmful metabolites, thereby optimizing the functions and structures of microbial communities in the sediments. This review further elucidates the ecological effects of CaO₂ on microbial communities, revealing its mechanistic role as an ecological remediation material in regulating microbial ecosystems within aquatic sediments. These findings provide significant theoretical references and scientific foundations for ecological restoration of waterbody sediments.

[Objective] To investigate the bio-weathering effects and mechanisms of Acidithiobacillus ferrooxidans on granite under acidic conditions (pH 2.0). [Methods] A 36-day immersion experiment was conducted, comparing the microbial group, acid solution group (pH 2.0, H₂SO₄), and pure culture medium (control) group. Physicochemical parameters [pH, redox potential (Eh), and electrical conductivity (EC)] of the soultion, surface chromaticity (CIE-Lab) of granite, and mineral dissolution characteristics were analyzed. [Results] The microbial group significantly accelerated granite weathering, forming a distinct weathered layer on the surface after 9 days. During the initial phase (0‒3 days), plagioclase dissolution caused a pH increase followed by stabilization. Fe³⁺ accumulation-dominated Eh and EC were regulated by both the initial ion background and weathering products. After bio-weathering, the granite exhibited a decrease of 11.6 in L* (reduced brightness), an increase of 6.8 in a* value (enhanced reddish-brown tone), and an increase of 9.6 in b* value (increased bluish tone). Surface reddish-brown areas were directly correlated with jarosite deposition. [Conclusion] Under acidic conditions, A. ferrooxidans accelerate granite weathering via Fe³⁺-mediated redox reactions. The chromaticity parameters (ΔL*, Δa*, and Δb*) and morphological characteristics serve as indicators for rapidly assessing weathering intensity. These findings provide a novel basis for evaluating weathering risks caused by acid mine wastewater in surrounding rocks and guiding ecological remediation.