Removal of phosphorus from wastewater by Diutina rugosa BL3: Efficiency and pathway

Simultaneous aerobic nitrogen and phosphorus removal by novel halotolerant fungus Mucor circinelloides SNDM1: Function and metabolism pathway

Fungi capable of simultaneous nitrogen and phosphorus removal from wastewater is rarely found. Here, a novel fungal strain (SNDM1) performing heterotrophic nitrification, aerobic denitrification, and phosphate removal was isolated and identified as Mucor circinelloides. The favorable nutrient removal conditions by the strain using glucose were C/N ratio of 25-30, salinities of 0 %-3 %, and pH of 7.5. Strain SNDM1 achieved ammonium, nitrite, nitrate, and phosphate removal rates of 5.23, 10.08, 4.88, and 0.97 mg/L/h. Nitrogen balance indicated that gaseous (18.60 %-24.55 %) and intracellular nitrogen (43.76 %-70.63 %) were primary fate of initial nitrogen. Enzyme activity revealed that ammonium removal occurred through heterotrophic nitrification and aerobic denitrification. Removed phosphorus was mainly transformed into cell membranes (56 %-64 %) and extracellular polymeric substances (20 %-26 %). Orthophosphate was the major intracellular phosphorus species, while polyphosphate and pyrophosphate existed extracellularly. These findings highlight the potential of this fungal strain for bioremediating polluted wastewater.

Unraveling the effects and mechanisms of antibiotics on aerobic simultaneous nitrogen and phosphorus removal by Acinetobacter indicus CZH-5

The effects of antibiotics, such as tetracycline, sulfamethoxazole, and ciprofloxacin, on functional microorganisms are of significant concern in wastewater treatment. This study observed that Acinetobacter indicus CZH-5 has a limited capacity to remove nitrogen and phosphorus using antibiotics (5 mg/L) as the sole carbon source. When sodium acetate was supplied (carbon/nitrogen ratio = 7), the average removal efficiencies of ammonia-N, total nitrogen, and orthophosphate-P increased to 52.46 %, 51.95 %, and 92.43 %, respectively. The average removal efficiencies of antibiotics were 84.85 % for tetracycline, 39.32 % for sulfamethoxazole, 18.85 % for ciprofloxacin, and 23.24 % for their mixtures. Increasing the carbon/nitrogen ratio to 20 further improved the average removal efficiencies to 72.61 % for total nitrogen and 97.62 % for orthophosphate-P (5 mg/L antibiotics). Additionally, the growth rate and pollutant removal by CZH-5 were unaffected by the presence of 0.1-1 mg/L antibiotics. Transcriptomic analysis revealed that the promoted translation of aceE, aarA, and gltA genes provided ATP and proton -motive forces. The nitrogen metabolism and polyphosphate genes were also affected. The expression of acetate kinase, dehydrogenase, flavin mononucleotide enzymes, and cytochrome P450 contributed to antibiotic degradation. Intermediate metabolites were investigated to determine the reaction pathways.

Genomics and metabolic characteristics of simultaneous heterotrophic nitrification aerobic denitrification and aerobic phosphorus removal by Acinetobacter indicus CZH-5

This study provides for the first time a systematic understanding of Acinetobacter indicus CZH-5 performance, metabolic pathway and genomic characteristics for aerobic nitrogen (N) and phosphorus (P) removal. Acinetobacter indicus CZH-5 showed promising performance in heterotrophic nitrification aerobic denitrification and aerobic phosphorus removal. Under optimal conditions, the maximum ammonia-N, total nitrogen and orthophosphate-P removal efficiencies were 90.17%, 86.33%, and 99.89%, respectively. The wide tolerance range suggests the strong environmental adaptability of the bacteria. The complete genome of this strain was reconstructed. Whole genome annotation was used to re-construct the N and P metabolic pathways, and related intracellular substance metabolic pathways were proposed. The transcription levels of related functional genes and enzyme activities further confirmed these metabolic mechanisms. N removal was achieved via the nitrification-denitrification pathway. Furthermore, CZH-5 exhibited significant aerobic P uptake, with phosphate diesters as the main species of intracellular P.

Aerated Static Pile Composting for Industrial Biowastes: From Engineering to Microbiology

This work demonstrated the feasibility of an industrial-scale aerated static pile composting system for treating one of the common biowastes-soybean curd residue. The mixing ratios of the feedstock were optimized to achieve a carbon-nitrogen ratio and a moisture level in the ranges of 25-35 and 60-70%, respectively. This open-air composting system required 6-7 months to obtain a mature compost. Solvita and seed germination tests further confirmed the maturity of the compost, with 25% compost extract concentration yielding the best germination index in the absence of phytotoxicity. The bacterial and fungal compositions of the compost piles were further examined with metagenomic analysis. Thermoactinomyces spp., Oceanobacillus spp., and Kroppenstedtia spp. were among the unique bacteria found, and Diutina rugosa, Thermomyces dupontii, and Candida taylorii were among the unique fungi found in the compost piles, suggesting the presence of good microorganisms for degrading the organic biowastes.

Feed nutritional composition affects the intestinal microbiota and digestive enzyme activity of black soldier fly larvae

Introduction

Using black soldier fly larvae (BSFLs) to treat food waste is one of the most promising environmental protection technologies.

Methods

We used high-throughput sequencing to study the effects of different nutritional compositions on the intestinal microbiota and digestive enzymes of BSF.

Results

Compared with standard feed (CK), high-protein feed (CAS), high-fat feed (OIL) and high-starch feed (STA) had different effects on the BSF intestinal microbiota. CAS significantly reduced the bacterial and fungal diversity in the BSF intestinal tract. At the genus level, CAS, OIL and STA decreased the Enterococcus abundance compared with CK, CAS increased the Lysinibacillus abundance, and OIL increased the Klebsiella, Acinetobacter and Bacillus abundances. Diutina, Issatchenkia and Candida were the dominant fungal genera in the BSFL gut. The relative abundance of Diutina in the CAS group was the highest, and that of Issatchenkia and Candida in the OIL group increased, while STA decreased the abundance of Diutina and increased that of Issatchenkia. The digestive enzyme activities differed among the four groups. The α-amylase, pepsin and lipase activities in the CK group were the highest, and those in the CAS group were the lowest or the second lowest. Correlation analysis of environmental factors showed a significant correlation between the intestinal microbiota composition and digestive enzyme activity, especially α-amylase activity, which was highly correlated with bacteria and fungi with high relative abundances. Moreover, the mortality rate of the CAS group was the highest, and that of the OIL group was the lowest.

Discussion

In summary, different nutritional compositions significantly affected the community structure of bacteria and fungi in the BSFL intestinal tract, affected digestive enzyme activity, and ultimately affected larval mortality. The high oil diet gave the best results in terms of growth, survival and intestinal microbiota diversity, although the digestive enzymes activities were not the highest.

Rapid simultaneous removal of nitrogen and phosphorous by a novel isolated Pseudomonas mendocina SCZ-2

Nitrogen (N) and phosphorous (P) removal by a single bacterium could improve the biological reaction efficiency and reduce the operating cost and complexity in wastewater treatment plants (WWTPs). Here, an isolated strain was identified as Pseudomonas mendocina SCZ-2 and showed high performance of heterotrophic nitrification (HN) and aerobic denitrification (AD) without intermediate accumulation. During the AD process, the nitrate removal efficiency and rate reached a maximum of 100% and 47.70 mg/L/h, respectively, under optimal conditions of sodium citrate as carbon source, a carbon-to-nitrogen ratio of 10, a temperature of 35 °C, and shaking a speed of 200 rpm. Most importantly, the strain SCZ-2 could rapidly and simultaneously eliminate N and P with maximum NH₄⁺-N, NO₃^--N, NO₂^--N, and PO₄^3--P removal rates of 14.38, 17.77, 20.13 mg N/L/h, and 2.93 mg P/L/h, respectively. Both the N and P degradation curves matched well with the modified Gompertz model. Moreover, the amplification results of functional genes, whole genome sequencing, and enzyme activity tests provided theoretical support for simultaneous N and P removal pathways. This study deepens our understanding of the role of HN-AD bacteria and provides more options for simultaneous N and P removal from actual sewage.

Removal of Phosphorus with the Use of Marl and Travertine and Their Thermally Modified Forms-Factors Affecting the Sorption Capacity of Materials and the Kinetics of the Sorption Process

The paper presents new reactive materials, namely marl and travertine, and their thermal modifications and the Polonite^® material, analyzing their phosphorus removal from water and wastewater by sorption. Based on the experimental data, an analysis of the factors influencing the sorption capacity of the materials, such as the material dose, pH of the initial solution, process temperature, surface structure, and morphology, was performed. Adsorption isotherms and maximum sorption capacities were determined with the use of the Langmuir, Freundlich, Langmuir-Freundlich, Tóth, Radke-Praunitz, and Marczewski-Jaroniec models. The kinetics of the phosphorus sorption process of the tested materials were described using reversible and irreversible pseudo-first order, pseudo-second order, and mixed models. The natural materials were the most sensitive to changes in the process conditions, such as temperature and pH. The thermal treatment process stabilizes the marl and travertine towards materials with a more homogeneous surface in terms of energy and structure. The fitted models of the adsorption isotherms and kinetic models allowed for an indication of a possible phosphorus-binding mechanism, as well as the maximum amount of this element that can be retained on the materials' surface under given conditions-raw marl (43.89 mg P/g), raw travertine (140.48 mg P/g), heated marl (80.44 mg P/g), heated travertine (282.34 mg P/g), and Polonite^® (54.33 mg P/g).

A novel Pseudomonas aeruginosa strain performs simultaneous heterotrophic nitrification-aerobic denitrification and aerobic phosphate removal

Nitrogen and phosphate removal from wastewater relies on different functional bacteria. In this study, a novel strain affiliated with Pseudomonas aeruginosa was isolated from activated sludge by gradient dilution and performed heterotrophic nitrification-aerobic denitrification and aerobic phosphate removal (HNADPR). The strain showed an ammonium removal efficiency of 87% and a phosphate removal efficiency of 97% under optimal conditions, such as C/N ratio of 10, P/N ratio of 0.1, temperature of 30°C, and pH of 7.5-8.5. The modified Gompertz model could fit well the heterotrophic ammonium nitrification, aerobic nitrite/nitrate denitrification, and aerobic phosphate removal processes. Functional gene amplification indicated that ammonium removal followed the complete HN-AD pathway (NH₄⁺ → NH₂OH → NO₂^- → NO₃^- → NO₂^- → NO → N₂O → N₂). Phosphate removal only occurred under aerobic conditions and ceased under anaerobic conditions. In successive aerobic cycles, the strain persistently took up phosphate. In wastewater, phosphate was aerobically converted into cell membrane, intracellular and extracellular polymeric substrates (EPS). Phosphorus in the form of phosphate monoester was pooled in EPS. A hypothetic aerobic phosphate removal model for strain SNDPR-01 is proposed to improve our understanding of the novel bacterial function of HNADPR.

Phosphorus removal from municipal wastewater through a novel Trichosporon asahii BZ: Performance and mechanism

A yeast BZ was screened from a laboratory-scale anaerobic/aerobic reactor and designated as Trichosporon asahii through 26S rDNA gene sequence analysis. The screened BZ abated over 70% of phosphorus in municipal sewage with 2-10 mg/L phosphorus in the appropriate conditions. The yeast BZ had strong adaptability to pH and the dissolved oxygen, but the cultivation temperature, carbon source, the ratio of C/P and the ratio of N/P had a critical influence on the phosphorus abatement performance of yeast BZ. The analysis of phosphorus concentration in the wastewater, cells, and extracellular polymeric substances (EPS) suggested that about 55%-66% of the removed phosphorus was in the yeast cells and 34%-45% in the EPS. The proposed probable metabolic mechanism of phosphorus in yeast BZ showed that EPS acted as a dynamic phosphorous transfer station, and most of phosphorus was transferred into yeast cells through EPS transfer station. These findings have crucial implications for the development of a promising stable and easy-operation biological phosphorus abatement process for municipal wastewater treatment.

Response of the aerobic denitrifying phosphorus accumulating bacteria Pseudomonas psychrophila HA-2 to low temperature and zinc oxide nanoparticles stress

Performance and molecular changes of an aerobic denitrifying phosphorus accumulating bacteria Pseudomonas psychrophila HA-2 have been investigated under different temperatures and ZnO nanoparticles (NPs) exposures. Strain HA-2 removed 95.7% of total nitrogen (TN) and 24.6% of phosphorus at 10 °C, which was attributed to the joint up-regulation of intracellular energy metabolism and ribosome. Moreover, with the increase of ZnO NPs from 0 to 100 mg/L, TN and phosphurs removal efficiencies decreased from 95.7% to 44.5% and 24.6% to 6.8% at 10 °C, respectively, whereas phosphorus removal rate increased from 10.5% to 24.5% at 20 °C. Further transcriptomics and proteomics revealed that significant down-regulation of purine and amino acid metabolisms was the main reason for the inhibitory effect at 10 °C, while the up-regulation of antioxidant pathways and functional genes expressions was responsible for the promoted phosphorus accumulation at 20 °C. This study provides a potential solution for improving biological nutrients removal processes in winter months.