Biodegradation of Sulfonamide Antibiotics by Microalgae: Mechanistic Insights into Substituent-Induced Effects

Microalgae are a sustainable environmentally friendly wastewater treatment technology that has attracted much attention for use in the purification of antibiotic-containing wastewater. However, research into the mechanisms involved in microalgal antibiotic degradation is still in the initial stages, especially concerning the relationship between pollutant structure and removal rate. This study comprehensively analyzed the antibiotic biodegradation mechanisms in microalgae from a molecular structure perspective, examining four sulfonamide antibiotics (SAs) with different substituents as representative pollutants. Microalgae exhibited removal efficiencies of 86.15, 74.24, 60.14, and 46.60% for sulfathiazole, sulfamethazine, sulfadiazine, and sulfamethoxazole, respectively. It is noteworthy that cytochrome p450 (CYP450) played a central catalyzing role in their metabolism. Further analysis of molecular dynamics simulations and density functional theory calculations revealed that the geometric differences and electronic effect variations caused by the substituents significantly affected the catalytic activity of CYP450 as well as the overall reactivity of the SAs, resulting in different removal rates. Overall, SAs with high binding energy, low energy gap, and high electrophilicity indices were more readily catalyzed by CYP450 as evidenced by the degradation pathways. These results provide valuable insights at the molecular level into how different substituents affect the degradation rate of SAs in microalgae

MOESM1 of Rapid in vivo lipid/carbohydrate quantification of single microalgal cell by Raman spectral imaging to reveal salinity-induced starch-to-lipid shift

Additional file 1: Figure S1. The stability test of our Raman setup over 6 hour’s measurement. Figure S2. The raw data without fluorescence background subtraction calculations for the data shown in Fig. 2. Figure S3. The TEM images of microalgal cells under different stress conditions

MOESM2 of Combined cell-surface display- and secretion-based strategies for production of cellulosic ethanol with Saccharomyces cerevisiae

Additional file 2: Figure S2. Time-course profiles of cell growth using host strain BY4741 and recombinant yeast strains in YPD medium. Each strain was inoculated in YPD medium to an initial OD660 of 0.05 and then cultured aerobically at 30 °C, 150 rpm for 72 h. For each strain, data are presented as the mean ¹ SD from three independent experiments

MOESM1 of Combined cell-surface display- and secretion-based strategies for production of cellulosic ethanol with Saccharomyces cerevisiae

Additional file 1: Figure S1. Relative transcription levels of cellulolytic enzyme-encoding genes in recombinant yeast strains. Gene ACT1 was used as the internal standard. The relative transcription levels were shown normalized to the level observed in strain EG-D-CBHI-D, whose relative transcription level was defined as 1. For each strain, data are presented as the mean Âą SD from three independent experiments

MOESM1 of Cell growth and lipid accumulation of a microalgal mutant Scenedesmus sp. Z-4 by combining light/dark cycle with temperature variation

Additional file 1. Figure S1. Effects of light/dark cycles on accumulation of pigment molecules and photosynthetic efficiency under mixotrophic condition. Figure S2. Temperature variation applied in this study. Table S1. The compositions of fatty acids (mass percentage) of microalgal mutant Z-4 at different light–dark cycles under autotrophic condition. Table S2. The compositions of fatty acids (mass percentage) of microalgal mutant Z-4 at different light–dark cycles under mixotrophic condition

Magnetic Nanoscale Zerovalent Iron Assisted Biochar: Interfacial Chemical Behaviors and Heavy Metals Remediation Performance

It has been reported that zerovalent iron can help biochar improve efficiency in heavy metal (HM) absorption, but the surface chemical behaviors and HM removal mechanisms remain unclear. We successfully synthesized the magnetic nanoscale zerovalent iron assisted biochar (nZVI-BC). The porosity, crystal structure, surface carbon/iron atom state, and element distribution were comprehensively investigated to understand nZVI-BC’s interfacial chemical behaviors and HM removal mechanisms. We clearly revealed the formation of a nanoscale Fe⁰ core–Fe₃O₄ shell on the surface/pores/channels of biochar. With the combination of iron nanoparticles and biochar, C–O/COOH groups were cracked with the formation of CO/CC, indicating the C–O–Fe acted as an electron acceptor during the reduction reaction. We also demonstrated that the stabilization was dramatically improved in the nZVI-BC, while more reduced iron and better homogeneity were observed. These results, showing the surface chemical behaviors of nZVI-BC, would help increase our understanding of the HM removal mechanisms. Moreover, our demonstration of the superior removal ability of multiple HM (Pb²⁺, Cd²⁺, Cr⁶⁺, Cu²⁺, Ni²⁺, Zn²⁺) from a solution can provide a breakthrough in making a feasible material for removing HM from polluted water resources

Distinct Mechanisms on Accelerating Electron Transfer to Facilitate Two-Stage Anaerobic Digestion Modulated by Various Microalgae Biochar

Microalgae-derived biochar are promising candidates to accelerate electron transfer during anaerobic digestion (AD) due to inherent advantages, but the mechanisms are unclear since they are highly related to microalgae species. In this work, distinct electron transfer mechanisms modulated by biochar derived from Scenedesmus sp. (SBC) and Chlorella sp. (CBC) were investigated during two-stage AD. Overall, adding biochar enhanced direct interspecies electron transfer (DIET) by increasing the relative abundance of related microorganisms like Firmicutes and Methanosaeta. Furthermore, SBC showed a foamy honeycomb structure with abundant functional groups, a rough surface, and irregular holes, which provided habitats for microorganism colonization and acted as an electron conductor for facilitating conductive material-mediated DIET (i.e., cDIET). Meanwhile, CBC showed a closed spherical granule structure having a smooth surface and low porosity, leading to stack of microorganisms on the biochar surface and causing bioelectrically triggered DIET (i.e., bDIET) via upregulated secretion of Flavins and C-type cytochromes. Results indicate that the electron transfer rate via bDIET was one order of magnitude higher than that via cDIET, resulting in a 53.9% increase on H2 yield and a 9.1% increase on CH4 yield in the CBC group compared to SBC group. These findings can enrich knowledge gaps of electron transfer mechanisms modulated by microalgae biochar and may inspire more efficient AD processes

Dually Prewetted Underwater Superoleophobic and under Oil Superhydrophobic Fabric for Successive Separation of Light Oil/Water/Heavy Oil Three-Phase Mixtures

Remediation of oil spills requires new technologies to separate light oil/water/heavy oil mixtures. Low-cost, biological, and environmentally friendly materials are needed to treat water pollution caused by oils. In this study, a corn straw powder (CSP)-coated fabric (CSPF) was fabricated by spraying waste CSP and polyurethane onto amphiphilic cotton fabric, and thus, the wettability of CSPF is enhanced by taking advantage of the hierarchical structure and increased surface roughness. Therefore, the CSPF could be dually prewetted (DCSPF) with both water and oil, and it showed underwater superoleophobic and under oil superhydrophobic properties without any further chemical modification. When applied to light oil/water/heavy oil separation, the DCSPF could be used to successively separate light oil/water/heavy oil three-phase mixtures under gravity with a high separation efficiency and flux. In addition, the DCSPF showed excellent structural and chemical stability according to repeated cycling and corrosive solution/oil separation experiments. The results of this study are of value in providing a simple, low-cost, and environment-friendly approach for application in the field of successive separation of light oil/water/heavy oil three-phase mixtures