Mixed Culture Research Articles

A methyl esterase from Bifidobacterium longum subsp. longum reshapes the prebiotic properties of apple pectin by triggering differential modulatory capacity in faecal cultures.

Pectin structures have received increasing attention as emergent prebiotics due to their capacity to promote beneficial intestinal bacteria. Yet the collective activity of gut bacterial communities to cooperatively metabolize structural variants of this substrate remains largely unknown. Herein, the characterization of a pectin methylesterase, BpeM, from Bifidobacterium longum subsp. longum, is reported. The purified enzyme was able to remove methyl groups from highly methoxylated apple pectin, and the mathematical modelling of its activity enabled to tightly control the reaction conditions to achieve predefined final degrees of methyl-esterification in the resultant pectin. Demethylated pectin, generated by BpeM, exhibited differential fermentation patterns by gut microbial communities in invitro mixed faecal cultures, promoting a stronger increase of bacterial genera associated with beneficial effects including Lactobacillus, Bifidobacterium and Collinsella. Our findings demonstrate that controlled pectin demethylation by the action of a B. longum esterase selectively modifies its prebiotic fermentation pattern, producing substrates that promote targeted bacterial groups more efficiently. This opens new possibilities to exploit biotechnological applications of enzymes from gut commensals to programme prebiotic properties.

POLA PENDIDIKAN MULTIKULTURAL DI SEKOLAH DASAR ISLAM TERPADU BUAH HATI SINTANG

Special schools with a unique vision, curriculum and educational environment are very attractive to people in choosing education for their children. Sekolah Dasar Islam Terpadu Buah Hati Sintang is one of the attractions of the school with the greatest interest among the Sintang Muslim community. The aim of this research is to describe the pattern of multicultural education that occurs in Integrated Islamic elementary schools that combine two curricula. This research uses one case study research with qualitative data collection techniques. Data validity applied a process of triangulation of techniques and sources with inductive conclusion drawing. The research results show: (1) Sekolah Dasar Islam Terpadu Buah Hati Sintang has two curricula; the National curriculum and the Islamic curriculum, (2) The multicultural pattern developed is an expression of the integration of Malay and Javanese culture (mixed culture) but is patterned and developed in a strong Islamic spirit, (3) The curriculum process requires teachers and students to fulfill the dimensions and values of Islamic education as a whole, including Syakhsiyyah Islamiyyah, Tsaqofah Islamiyyah and Life Sciences. In order for the multicultural education dimension to take root in the educational process at Integrated Islamic Primary Schools, it is necessary to strengthen holistic pedagogy and peace education by combining 21st century skills capacities so as to increase the spirit of unity, brotherhood and solidarity at the internal and external levels of the educational unit.

Near-Infrared Photoimmunotherapy for Targeted Cell Elimination in Mixed 3D Cultures

Near-Infrared Photoimmunotherapy for Targeted Cell Elimination in Mixed 3D Cultures

Near-Infrared Photoimmunotherapy for Targeted Cell Elimination in Mixed 3D Cultures

Near-Infrared Photoimmunotherapy for Targeted Cell Elimination in Mixed 3D Cultures

Isolation and characterization of pure cultures for metabolizing 1,4-dioxane in oligotrophic environments.

1,4-Dioxane concentration in most contaminated water is much less than 1 mg/L, which cannot sustain the growth of most reported 1,4-dioxane-metabolizing pure cultures. These pure cultures were isolated following enrichment of mixed cultures at high concentrations (20 to 1,000 mg/L). This study is based on a different strategy: 1,4-dioxane-metabolizing mixed cultures were enriched by periodically spiking 1,4-dioxane at low concentrations (≤1 mg/L). Five 1,4-dioxane-metabolizing pure strains LCD6B, LCD6D, WC10G, WCD6H, and WD4H were isolated and characterized. The partial 16S rRNA gene sequencing showed that the five bacterial strains were related to Dokdonella sp. (98.3%), Acinetobacter sp. (99.0%), Afipia sp. (99.2%), Nitrobacter sp. (97.9%), and Pseudonocardia sp. (99.4%), respectively. Nitrobacter sp. WCD6H is the first reported 1,4-dioxane-metabolizing bacterium in the genus of Nitrobacter. The net specific growth rates of these five cultures are consistently higher than those reported in the literature at 1,4-dioxane concentrations <0.5 mg/L. Compared to the literature, our newly discovered strains have lower half-maximum-rate concentrations (1.8 to 8.2 mg-dioxane/L), lower maximum specific 1,4-dioxane utilization rates (0.24 to 0.47 mg-dioxane/(mg-protein ⋅ d)), higher biomass yields (0.29 to 0.38 mg-protein/mg-dioxane), and lower decay coefficients (0.01 to 0.02 d-1). These are characteristics of microorganisms living in oligotrophic environments.

Development and evaluation of test methods for the detection and enumeration of opportunistic waterborne pathogens from the hospital environment

Many Gram-negative bacteria other than Pseudomonas aeruginosa have been implicated in waterborne outbreaks, but standardized laboratory detection methods for these organisms have not been established. This study aimed to establish laboratory testing methodologies for six waterborne pathogens: Acinetobacter spp., Burkholderia spp., Cupriavidus spp., Delftia acidovorans, Elizabethkingia spp. and Stenotrophomonas maltophilia. Water samples were spiked by UK Health Security Agency laboratories and sent to the Glasgow Royal Infirmary laboratory for analysis. Water samples were spiked with either a pure culture of target organism or the target organism in water containing normal background flora, to ensure that the methodology could identify organisms from a mixed culture. Volumes of 100mL were filtered under negative pressure on to culture media and incubated at 30°C and 37°C. The incubation time was 7 days, with plates read on days 2, 5 and 7. Further identification of colonies was undertaken using matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS). Optimal recovery of organisms was obtained by culturing water samples on tryptic soy agar, chocolate bacitracin agar and pseudomonas selective agar. The optimal temperature for isolation was 30°C. The optimal incubation time was 5 days, and MALDI-TOF MS identified all test species reliably. The methodology described was able to detect the six tested waterborne pathogens reliably, and can be utilized by laboratories involved in testing water samples during outbreak investigations.

EcoHIV Infection of Primary Murine Brain Cell Cultures to Model HIV Replication and Neuropathogenesis.

EcoHIV is a chimeric HIV that replicates in mice in CD4+ T cells, macrophages, and microglia (but not in neurons), causing lasting neurocognitive impairment resembling neurocognitive disease in people living with HIV. The present study was designed to develop EcoHIV-susceptible primary mouse brain cultures to investigate the indirect effects of HIV infection on neuronal integrity. We used two EcoHIV clones encoding EGFP and mouse bone marrow-derived macrophages (BMM), mixed mouse brain cells, or enriched mouse glial cells from two wild-type mouse strains to test EcoHIV replication efficiency, the identity of productively infected cells, and neuronal apoptosis and integrity. EcoHIV replicated efficiently in BMM. In mixed brain cell cultures, EcoHIV targeted microglia but did not cause neuronal apoptosis. Instead, the productive infection of the microglia activated them and impaired synaptophysin expression, dendritic density, and axonal structure in the neurons. EcoHIV replication in the microglia and neuronal structural changes during infection were prevented by culture with an antiretroviral. In murine brain cell cultures, EcoHIV replication in the microglia is largely responsible for the aspects of neuronal dysfunction relevant to cognitive disease in infected mice and people living with HIV. These cultures provide a tool for further study of HIV neuropathogenesis and its control.

Degradation of pretilachlor and fenclorim and effects of these compounds on bacterial communities under anaerobic condition.

Pretilachlor and safener fenclorim are the main components of herbicides widely applied to control weeds. Although some pure cultures of bacteria and fungi which degraded these compounds under aerobic conditions were isolated, no isolated pretilachlor- and fenclorim-degrading bacterial strains under anaerobic condition had been available. In this study, the degradation of these compounds and the effects of them on bacterial community structures were investigated under anaerobic conditions. The dissipation rates of pretilachlor and fenclorim in slurries were in the order: soil from paddy field ≈ sediment from river > sediment from mangrove. Moreover, three pretilachlor-degrading bacterial strains (Pseudomonas sp. Pr1, Proteiniclasticum sp. Pr2 and Paracoccus denitrificans Pr3) and two fenclorim-degrading strains (Dechloromonas sp. Fe1 and Ralstonia pickettii Fe2) isolated from a slurry of paddy soil utilized the substrates as sole carbon and energy sources under anaerobic conditions. The degradation of pure pretilachlor and fenclorim at various concentrations by corresponding mixed pure cultures followed the Michaelis-Menten model, with the maximum degradation was 3.10 ± 0.31µM/day for pretilachlor, and 2.08 ± 0.18µM/day for fenclorim. During the degradation, 2-chloro-N-(2,6-diethylphenyl) acetamide and 2,6-dimethylaniline were produced in pretilachlor degradation, and benzene was a product of fenclorim degradation. The synergistic degradation of both substrates by all isolated bacteria reduced the metabolites concentrations accumulated in media. This study provides valuable information on effects of pretilachlor and fenclorim on bacterial communities in soil and sediments, and degradation of these substrates by isolated bacteria under anaerobic condition.

H2S-laden biogas triggers sulfur amino acids production in microbial protein synthesized during mixed culture fermentation by methane and sulfur oxidizing bacteria

Biogas can be converted into high-value bioproducts through fermentation processes. This study proposes a conversion platform where sulfide-rich biogas is utilized as the substrate for the growth of a mixed culture of methane- and sulfur-oxidizing bacteria for the production of high-value and protein-rich microbial biomass. The role of several process variables such as biomethane vs biogas, synthetic vs real biogas, biogas composition and H2S concentration during the fermentation process performed in bubble column reactors was evaluated in terms of biomass growth, yield and volumetric productivity, protein content and amino acids profile as well as microbial community composition and evolution. Despite the presence of 1500 ppm of equivalent H2S in the synthetic biomethane or biogas (CH4:CO2 ratio of 70:30), good performances in terms of biomass growth (559.9 ± 13.3–677.8 ± 46.8 mg of volatile suspended solids (VSS) per liter), biomass yield (0.042 ± 0.004–0.050 ± 0.08 mg VSS per mg of CH4-equivalent chemical oxygen demand (CH4-COD)) as well as protein content (51.9 ± 3.6% − 59.2 ± 3.6% g protein/g VSS) were achieved. The presence of increasing sulfide concentrations until 4000 ppm of equivalent H2S was well tolerated by the mixed culture and increased the production of valuable S-amino acids, i.e., cysteine and methionine (61.3 mg/g biomass and 58.3 mg/g biomass, respectively), which was up to 2.50 and 2.57 times higher than in the absence of sulfide, respectively.

Interactions between Aeromonas caviae and Yersinia enterocolitica isolated from a case of diarrhea: evaluation of antimicrobial susceptibility and immune response of infected macrophages.

Aeromonas species cause a wide spectrum of human diseases, primarily gastroenteritis, septicemia, and wound infections. Several studies have shown that about 40% of these cases involve mixed or polymicrobial infections between Aeromonas spp. and bacteria from other genera. However, the immune response of macrophages in front of the bacteria present in the mixed infections, as well as their impact on antimicrobial therapy, have not been investigated. This study evaluated the cell damage and immune response of the mouse macrophage BALB/c cell line (J774A.1) after performing a single and a mixed infection with a strain of Aeromonas caviae and Yersinia enterocolitica, both recovered from the same fecal sample from a patient with diarrhea. Macrophage cell damage was measured by the release of lactate dehydrogenase (LDH) while the immune response was evaluated studying the expression by RT-qPCR of six relevant immune-related genes. Additionally, the antimicrobial susceptibility pattern of the single and mixed strains in front of seventeen antibiotics was evaluated to determine the potential impact on the infection treatment. Macrophages infected with the mixture of the two strains showed a higher cell damage in comparison with the single infections and the immune-related genes, i.e., cytokines and chemokines genes (TNF-α, CCL20), and apoptotic and pyroptotic genes (TP53 and IL-1β) were overexpressed. After infection with the mixed cultures, an increase in the antimicrobial resistance was observed for ciprofloxacin, trimethoprim, chloramphenicol, gentamicin and ertapenem. This study increased the knowledge about the synergetic effect of the bacteria involved in mixed infection and on their potential impact on the treatment and evolution of the infection.

Cultivation of Chlorella protothecoides in the medium amended with cigarette butt leachate wastewater for enhanced biomass and macromolecular productions

Microalgal cultivation in wastewater can significantly reduce the nutrient requirements and helps in wastewater management. In this study, Chlorella protothecoides was cultured on cigarette butt leachate admixed with culture medium. The cigarette butt leachate concentrations in the culture medium were set from 0 % to 100 % and a maximum biomass production was achieved at 60 % concentration (1.24 g L−1). The lipid content of Chlorella protothecoides was increased by 9.98 %, carbohydrate content by 40.93 % and protein content by 42.93 % with 60 % of cigarette butt leachate concentration as compared to the control. Water quality analysis after microalgal cultivation revealed that the N and P elements in the cigarette butt leachate wastewater were removed completely by the microalgal growth. Life cycle assessment (LCA) analysis was carried out to evaluate the environmental sustainability of the process, which has revealed that the cigarette butt leachate wastewater has significant reduction in the environmental impacts with a CO2 emission reduction up to 338 %. The study empirically suggested that the cigarette butt leachate mixed culture medium has potentially promoted the growth, lipid and protein in Chlorella protothecoides which can improve the upstream economics along with the environmental benefits of waste management.

Bioremediation of phenolic compounds in coal‐contaminated environments: Bio‐kinetic studies using a mixed bacterial culture

AbstractTwo distinct bacterial strains were combined in a mixed culture to investigate the degradation of phenol. The mixed cultures consisting of species like Rhodococcus and Bacillus, were isolated from the waste effluent collected from Dankuni coal complex (DCC) in West Bengal. The experimental phenol biodegradation were performed batch wise at an optimized temperature and pH conditions of 37°C and 7.0 for a wide range of phenol concentrations initially, with saline solutions which is not supplemented with nutrients initially. Experimental results concluded a highest possible specific growth rate at 150 mg/L for phenol biodegradation of 2400 mg/L within a span of 72 h. Several significant physicochemical parameters were investigated in order to determine the ideal conditions for phenol breakdown. It was also observed that a spectroscopic study of the intermediate at 260 nm of the phenol biodegradation commenced through the formation of a cis, cis intermediate, indicating ortho‐cleavage pathway. A simulated substrate utilization and growth profiles was obtained by using substrate inhibition model equation using MATLAB R2017a were used to compare for the validation of the obtained experimental growth and substrate characterization data.

Chemical characterization of Thymus zygis L. (thyme) and Elettaria cardamomum L. (cardamom) essential oils and investigation of their inhibitory potentials against cervicovaginal Escherichia coli isolates

IntroductionThe cervicovaginal microbiota plays a crucial role in women's well-being and reproductive health. This study initially focuses on identifying the chemical components of the essential oils (EOs) from Elettaria cardamomum L. (cardamom) (Ec) and Thymus zygis L. (thyme) (Tz). Subsequently, this study aims to determine the antimicrobial and biofilm inhibitory effects of these EOs against both cervicovaginal mixed cultures and the microbial strains isolated from them. MethodsThe compositions of EOs were determined by GC–MS analysis using an Agilent 7890B GC/5977A Series MSD System. Cervicovaginal samples were obtained from two women presenting complaints of a strong odor and vaginal discharge. Samples were collected from the cervix using a sterile cytobrush, ensuring no contact with the urethra, rectum, or external parts of the vagina. The cytological examination was conducted using Papanicolaou staining. Isolated microorganisms were identified through 16S Ribosomal RNA Gene Sequence Analysis and characterized using antibiogram tests. Antimicrobial tests of the EOs were performed by broth microdilution and disc diffusion methods. Biofilm formation was assessed using a crystal violet binding assay. ResultsThe major components of Ec EO were α-terpinyl acetate (41.95 %) and eucalyptol (28.58 %), whereas Tz EO contained significant amounts of o-cymene (38.76 %), carvacrol (22.66 %), and thymol (20.69 %). Escherichia coli codes OR651248 and OR651249 were isolated from CV 6 and CV 7 mixed cultures, respectively. E. coli OR651248 demonstrated a higher antibiotic resistance level than E. coli OR651249. Biofilm formation by mixed cultures was significantly higher than that by E. coli isolates (P < 0.05). The Ec EO displayed minimal to no effect against both mixed cultures, showing zero inhibition zone, 500 μL/mL minimum inhibitory concentrations (MICs), and 500 μL/mL minimum microbicidal concentrations (MMCs). However, the Tz EO exhibited antimicrobial activity against both mixed cultures and the E. coli isolates, with inhibition zones > 15 mm and MICs/MMCs < 4 μL/mL (P < 0.05). In all microbial cultures, 0.5 MIC of both EOs inhibited biofilm formation by more than 80 %. ConclusionThe Tz EO exhibits promising potential as an antimicrobial and biofilm inhibitory agent for managing cervicovaginal E. coli infections.

Differentiation and quantification of extracellular polymeric substances from microalgae and bacteria in the mixed culture

Extracellular polymeric substances (EPS) play significant roles in the formation, function, and interactions of microalgal-bacteria consortia. Understanding the key roles of EPS depends on reliable extraction and quantification methods, but differentiating of EPS from microalgae versus bacteria is challenging. In this work, cation exchange resin (CER) and thermal treatments were applied for total EPS extraction from microalgal-bacteria mixed culture (MBMC), flow cytometry combined with SYTOX Green staining was applied to evaluate cell disruption during EPS extraction, and auto-fluorescence-based cell sorting (AFCS) was used to separate microalgae and bacteria in the MBMC. Thermal extraction achieved much higher EPS yield than CER, but higher temperature and longer time reduced cell activity and disrupted the cells. The highest EPS yield with minimal loss of cell activity and cell disruption was achieved using thermal extraction at 55℃ for 30 min, and this protocol gave good results for MBMC with different microalgae:bacteria (M:B) mass ratios. AFCS combined with thermal treatment achieved the most-efficient biomass differentiation and low EPS loss (<4.5 %) for the entire range of M:B ratios. EPS concentrations in bacteria were larger than in microalgae: 42.8 ± 0.4 mg COD/g TSS versus 9.19 ± 0.38 mg COD/g TSS. These findings document sensitive and accurate methods to extract and quantify EPS from microalgal-bacteria aggregates.

Strategic implementation of upflow microbubble airlift photocatalytic process to control heavy metal resistant-MDR bacteria and the associated genes in wastewater

The emergence of multidrug resistance (MDR) and heavy metal resistance (HMR) in bacterial pathogens and genes through mobile genetic elements (MGEs) from wastewater effluents needs to be eradicated using green technology. HMR is critical to controlling antimicrobial resistance but has been neglected in most photocatalytic disinfection (PCD) studies. Advanced photocatalysis in antimicrobial studies requires a strategic approach to enhance the disinfection efficiency. This study applied an optimized upflow airlift photocatalytic reactor (UAPR) with microbubble air and blue light to remove the antimicrobial resistance (HMR–MDR bacteria (HMR–MDRB), HMR genes (HMRGs), antibiotic resistant genes (ARGs) and MGEs) and inhibit pathogenicity in a mixed culture of high-strength HMR–MDRB isolated from wastewater. Stable dissolved oxygen (DO) supplementation and blue light significantly affected the HMRGs and MGE reduction, resulting in enhanced disinfection activity (30 %) and reaction time (60 min) required for the complete inactivation of HMR-MDRB mixed culture. The process effectively reduced the blaNDM-1 (3.37 log), pbrT (2.18 log), intl1 (2.16 log), and tn916/1545 (4.07 log), with a PCD rate constant (kg) of 0.0515 min−1, 0.0359 min−1, 0.0292 min−1, and 0.0662 min−1, respectively. Process mechanism studies showed that the stable supplementation of DO was a critical factor in controlling the type of reactive oxygen species (ROS), resulting in type II ROS, 1O2, as the critical free radical contributing to the reduction of ARGs and integron, whereas h+ was the ROS for pbrT and transposon.

Boosting Capsicum annuum Growth Through Non-native Endophytic Bacterial Consortium

Abstract Organic and natural sources of bio-stimulant have a great expectancy to boost green agriculture practices for sustainable, safe, and smart cultivation of crops. In that regard, beneficial endophytic bacteria have great potential. They have unique features in promoting plant growth by colonizing and establishing well in plant roots. In this study, endophytes isolated from the roots of moringa, neem, sesbania, and chilli were screened for crop’s growth-enhancing activities, such as phosphorus (P) solubilization, 1-aminocyclopropane-1-carboxylic-acid deaminase (ACC deaminase) production, and indole-acetic acid (IAA) production. The phosphorus solubilization, indole-acetic acid production, and ACC deaminase production values fall in the range of 55–88 ppm, 20–164 ppm, and 0.317–0.375 mM, respectively. Chilli seeds’ three highest vigor index (VI) values were attained by MR10 (12,457 VI), MR3 (9450 VI), and MR13 (8730 VI). MR13 showed the highest seed germination energy (221%), followed by MR1 (178%) and MR3 (156%). The promising endophytes were tested on chilli seedlings as single and mixed inoculum treatments to study the efficiency of root colonization. Mixed cultures containing CKR8 and MR13 exhibited the highest seedling height (17.0 cm), followed by MR13, MR10, and MR13 (16.8 cm) compared to the control (12.6 cm). A single culture of MR10 (109.0 g and 13.53 cm2) and a mixed culture of MR10 and MR13 (100.0 g and 13.09 cm2) showed the maximum root length and surface area, respectively. The highest relative chlorophyll content was recorded by MR10 and MR13 (40.3 SPAD value), followed by MR13, MR3, and CKR8 (36.8 SPAD value). The non-native endophytic bacteria, MR13, Streptomyces panaciradicis (GenBank accession no. OM001090), and MR3, Bacillus subtilis (GenBank accession no. OM714810), could colonize the roots and improve the growth of chilli at the seedling growth stage. Graphical Abstract

Growth enhancement and changes in bacterial microbiome of cucumber plants exhibited by biopriming with some native bacteria

This study investigated the impact of a mixture of six endophytic bacterial strains isolated from cucumber plants on the growth and microbiome diversity of six cucumber traditionalvarieties and hybrids.Six bacterial species were isolated and identified by 16 s rRNA sequencing. All the bacteria showed plant growth promoting traits.Bacillus tequilensisshowed 80 % inhibition of the mycelia growth ofFusarium oxysporum f.sp.cucumarinum(Foc). Mixed culture of all the bacteria was prepared and applied back to the varieties and hybrids of cucumber plants through seed soaking. Plant growth characteristics indicated that the treated plants showed increased plant growth in terms of plant height, number of leaves, vine length, male:female flower ratio, number of fruits and fruit length. Bacteria treated plants of hybrid HiVeg Chitra recorded 19 cm increase in vine length compared to control plants. The matataxonomic analysis of leaf samples by Illumina sequencing highlighted a diverse bacterial community shift in treated plants, with significant increases in genera likeBacillusandStaphylococcus. The core microbiome analysis identified key genera such asBacillus, Staphylococcus, Sphingomonas, Methylobacterium, etc that could be pivotal in plant growth promotion.BacillusandStaphylococcus showed increased abundance in treated varieties, correlating with the observed in plant growth parameters thus indicating their role in growth promotion of cucumber plants. Endophytic bacterial species identified from cucumber plants when re-applied by seed soaking, they promote the plant growth by modulating the microbiome. The bacterial species identified in the study could be potential candidates as microbial bioinputs for cucumber cultivation.

Application of electric potential and Fe(Ⅲ) to stimulate perfluorooctanoic acid (PFOA) degradation using mixed culture anammox granules

Pollution by perfluorooctanoic acid (PFOA), a highly persistent and toxic substance, is commonly addressed with several approaches, but the need for post-treatment affects their environmental and economic sustainability. Biodegradation, which can efficiently degrade micropollutants in water under optimal conditions, offers a promising solution, but faces challenges from the persistence of the C-F bond and the high reactivity of F-. Despite recent use of various microorganisms for PFOA degradation, performance issues persist. In this study, we aimed to simulate PFOA degradation while mixed culture anammox granules oxidize NH4+ and to confirm the effects of electric potential and Fe(Ⅲ) applications on PFOA degradation. A control reactor containing only anammox granules exhibited NH4+ and PFOA removal efficiencies of 11.52% and 19.2%, respectively, with traceable biodegradation at 3.7%. In contrast, a reactor that applied both electric potential and Fe(Ⅲ) demonstrated enhanced removal efficiencies of 41.98% and 50.93%, with traceable biodegradation at 35.03%. Bio-electrochemical properties also improved, showing an average current generation of 331.95 μA and Coulombic efficiency of 141.79 ± 7.6%. This study shows that mixed-culture anammox granules with electric potential and Fe(Ⅲ) can be introduced for efficient PFOA biodegradation and provides the basis for further studies on overcoming the limitations of PFOA biodegradation.

Fungal Consortia Mediated Bio-Treatment of Organic Matter and Metals Uptake from Sewage Water: Maize Agro-Physiological Assessment

The present investigation aims to improve the efficiency of fungal mono- and mixed cultures in removing organic pollutants and metals from sewage water (SW) for further maize plant response assessments. The reduction in the organic load from the SW was harnessed using a co-culture consortium consisting of Aspergillus niger (KB5), Sordariomycetes sp. (D10), and Coniochaetaceae sp. (LB3). The testing results had evinced removal of up to 88% of the organic matter and more than 96%, 91%, 80%, and 47.6%, of removal percentages for Copper (Cu), Nickel (Ni), Cadmium (Cd), and Lead (Pb), respectively, with the developed fungal consortium [KB5 + D10 + LB3]. After treatment and lab experiments, a reuse of treated and untreated SW for plant irrigation was evaluated towards improving maize plant growth. Irrigation was conducted in pot experiments with three types of water: clean water (Control), untreated (USW), and treated SW by fungal consortia (TSW) and by station treatment plant STP (TSWP) using the randomized complete block (RCB) experimental design. Results of the pots trial revealed that the morphological parameters of SW-irrigated plants are slightly improved compared to water-irrigated plants. Data regarding assimilating area attributes indicated that the most significant enlargement of the assimilation area was observed with TSW-D (1/4) irrigation by 1051 cm2, followed by TSWP-D (0) by 953.96 cm2, then USW-D (1/4) by 716.54 cm2, as compared to plants irrigated with clean water (506.91 cm2). On average, the assimilation areas were larger by 51.76%, 46.86%, and 29.25% in TSW, USW, and TSWP-irrigated plants, respectively. Thus, SW irrigation supports the required qualities and quantities of microelements and water for plant growth. Oxidative stress assessment showed that irrigations with treated SW caused a significant decrease in both enzymatic and non-enzymatic antioxidants, depicting that the treatment lowered the stress of sewage water.

Upcycling nitrogen and curbing greenhouse gas emissions from wastewater through H2-driven assimilatory mixotrophic metabolism

Biological nitrogen assimilation is an emerging technique for the removal and upcycling of nitrogen from wastewater in the form of microbial protein (MP). For this purpose, a mixed hydrogen-oxidizing bacteria (HOB) culture capable of growing mixotrophically was evaluated for the treatment of synthetic and real wastewater under different carbon-to-nitrogen (C/N) ratios. The same mixed HOB culture was grown under heterotrophic conditions to compare treatment and process performances in terms of ammonium nitrogen (N-NH4+) removal and assimilation, chemical oxygen demand (COD) removal, CO2 release, biomass concentration, yield and protein content. Under mixotrophic conditions, the highest biomass concentration was 342.5 mg VSS∙L−1, doubling that obtained under heterotrophic conditions (161.2 mg VSS∙L−1). Discharge limits for both COD and total N were met under mixotrophic conditions, with nitrogen removal and assimilation into protein-rich biomass achieving up to 99 %. On the contrary, under heterotrophic conditions, the high content of residual nitrogen as nitrite (up to 26 mg∙L−1 of N-NO2−) did not allow to meet discharge limits for total N. The mixed HOB culture gave promising results in terms of biomass yield (0.32 g VSS·g CODH2+acetate−1) and protein content (up to 56 % of VSS) when grown mixotrophically. Under heterotrophic conditions, instead, the biomass yield (0.25 g VSS·g CODacetate−1) and protein content (35 %) were substantially lower. This study suggests that the H2-driven assimilatory mixotrophic metabolism can be successfully applied for wastewater treatment to produce effluents that meet discharge limits while mitigating greenhouse gas emissions (CO2 and N2O) and upcycling nitrogen into MP.