Biochar is one of the most concerned research hotspots at present, which is a stable and carbon-rich solid produced by pyrolysis of organic biomass under anoxic conditions. Biochar has abundant pore structure, functional groups, aromatic hydrocarbons and other characteristics, which enable it to improve soil physical and chemical properties, increase nutrient content, and regulate soil microbial community structure. In recent years, with the continuous research on biochar, the role of biochar in the remediation of heavy metal pollution has been further studied. The physical adsorption, ion exchange, electrostatic attraction, complexation reaction, mineral precipitation, redox and other functions of biochar are the main factors for repairing heavy metal ions. In addition, immobilization is the primary goal of biochar remediation of heavy metals in agricultural soils, because it can greatly reduce the risk of human health caused by heavy metals entering the food chain. This paper reviewed the current knowledge of biochar and its function in agricultural heavy metal soil. Based on the background of heavy metal pollution in agricultural soil in China, the possible remediation mechanism of biochar was discussed. It provides scientific basis for the development and application of biochar in the remediation of heavy metal pollution in agricultural soil in China.

Petroleum hydrocarbon compounds are recognized to be neurotoxic and xenobiotic organic pollutants, because they are presently a large environmental issue as a result of the increased mining of petroleum compounds and similar products, both of which have important environmental consequences. Petroleum products include cancer - causing compounds which can have a range of impacts on ecology biotic and abiotic variables, and leakage is generally induced by mistakes in pumping, transportation, and refining. Physical and biological procedures are commonly cleaned to separate petroleum from polluted areas. Both methods are efficient but can be costly. Because it is not very costly and leads to complete mineralization, bioremediation is the best and most advanced method for treating these polluted sites. Another very significant and successful natural technique for eliminating petroleum hydrocarbon environmental contaminants is microbial decomposition. Hydrocarbon contaminants could be deteriorated by a variety of indigenous microbes in water and soil. A variety of limiting variables have been identified that impact petroleum hydrocarbon biodegradation. This study outlines the aerobic and anaerobic microbiological breakdown of organic compounds, as well as the different variables that influence the process. Microbial deterioration could be regarded a vital aspect in the cleaning approach for petroleum hydrocarbon recovery, it can be inferred.

Biofilm formation has different stages and can be classified based on the bacterial strain, culture vessel, and the method employed. Biofilm formation is carried out in culture vessels to represent mode of infection in humans. Microbial concentration, growth medium, supplement, and incubation time are key factors to successfully form biofilm in a culture vessel. This study aimed to identify the optimum conditions for biofilm formation in a 96-well plate by culturing Pseudomonas aeruginosa and Streptococcus pyogenes. We utilized the infectious and pathogenic bacteria, P. aeruginosa and S. pyogenes strains. These bacteria were cultured in Mueller–Hinton Broth (MHB) and Tryptic Soy Broth (TSB) at two different optical densities OD₆₀₀ (0.05) and OD₆₀₀ (0.1). After a certain incubation time, the formed biofilm was stained by using 0.1% crystal violet. The stained bacteria were disaggregated and measured using a microplate reader. Biofilm was then classified based on bacterial adherence to the plate. Our results showed that P. aeruginosa and S. pyogenes biofilms were strongly formed on days 3 and 5 in MHB and TSB, respectively. However, the strongest biofilm formation was seen on day 3 after P. aeruginosa being incubated in MHB at OD₆₀₀ (0.1) and after S. pyogenes being incubated in MHB at OD₆₀₀ (0.05). Biofilm formation is ranged between weak, moderate, and strong in accordance with the density of bacterial adhesion. P. aeruginosa and S. pyogenes biofilms were optimized at specific OD₆₀₀ (0.1 and 0.05, respectively) for 3 days’ cultivation in MHB.

Dissolved organic matter (DOM) and Cu(II), originated from livestock manure, often co-exist in livestock effluents. The effects of DOM on adsorption of Cu(II) by adsorbent remain unknown, which may prevent the removal of Cu(II) from livestock effluents using the method of adsorption. In this study, the effects of DOM on adsorption behaviors of Cu(II) by Aliinostoc sp. YYLX235, a epiphytic cyanobacterium, were investigated. The results showed that Aliinostoc could effectively bind with Cu(II) and remove it from water. Rather than absorption, most of Cu(II) were bound on the cell surface through adsorption. The decay of Aliinostoc did not resulted in rapid release of Cu(II) into water. The amount of Cu(II) adsorbed by Aliinostoc through ion exchange and complexation was decreased by DOM addition.

Phenol is one of the main pollutants that have a serious impact on the environment and can even be very critical to human health. The biodegradation of phenol can be considered an increasingly important pollution control process. In this study, the degradation of phenol by Bacillus simplex was investigated for the first time under different growth conditions. Six different initial concentrations of phenol were used as the primary substrate. Culture conditions had an important effect on these cells' ability to biodegrade phenol. The best growth of this organism and its highest biodegradation level of phenol were noticed at pH 7, temperature 28 °C, and periods of 36 and 96 h, respectively. The GC-MS analysis of the bacterial culture sample revealed that further degradation of the catechol by 1,2-dioxygenase produce a cis, cis-mucconic acid via ortho-pathway and/or by 2,3-dioxygenase into 2-hydroxymucconic semialdehyde via meta-pathway.The highest biodegradation rate was perceived at 700 mg/L initial phenol concentration. Approximately 90% of the phenol (700 mg / L) was removed in less than 96 hours of incubation time. It was found that the Haldane model best fitted the relationship between the specific growth rate and the initial phenol concentration, whereas the phenol biodegradation profiles with time could be adequately described by the modified Gompertz model. The obtained parameters from the Haldane equation are: 1.05 h⁻¹, 9.14 ppm, and 329 ppm for Haldane's maximum specific growth rate, the half-saturation coefficient, and the Haldane’s growth kinetics inhibition coefficient, respectively. The Haldane equation fitted the experimental data by minimizing the sum of squared error (SSR) to 1.36x10^-3.