Bioremediation Of Environments Research Articles

Bacterial community structure analysis of sludge from Taozi lake and isolation of an efficient 17β-Estradiol (E2) degrading strain Sphingobacterium sp. GEMB-CSS-01

Environmental challenges arising from organic pollutants pose a significant problem for modern societies. Efficient microbial resources for the degradation of these pollutants are highly valuable. In this study, the bacterial community structure of sludge samples from Taozi Lake (polluted by urban sewage) was studied using 16S rRNA sequencing. The bacterial phyla Proteobacteria, Bacteroidetes, and Chloroflexi, which are potentially important in organic matter degradation by previous studies, were identified as the predominant phyla in our samples, with relative abundances of 48.5%, 8.3%, and 6.6%, respectively. Additionally, the FAPROTAX and co-occurrence network analysis suggested that the core microbial populations in the samples may be closely associated with organic matter metabolism. Subsequently, sludge samples from Taozi Lake were subjected to enrichment cultivation to isolate organic pollutant-degrading microorganisms. The strain Sphingobacterium sp. GEMB-CSS-01, tolerant to sulfanilamide, was successfully isolated. Subsequent investigations demonstrated that Sphingobacterium sp. GEMB-CSS-01 efficiently degraded the endocrine-disrupting compound 17β-Estradiol (E2). It achieved degradation efficiencies of 80.0% and 53.5% for E2 concentrations of 10 mg/L and 20 mg/L, respectively, within 10 days. Notably, despite a reduction in degradation efficiency, Sphingobacterium sp. GEMB-CSS-01 retained its ability to degrade E2 even in the presence of sulfanilamide concentrations ranging from 50 to 200 mg/L. The findings of this research identify potential microbial resources for environmental bioremediation, and concurrently provide valuable information about the microbial community structure and patterns within Taozi Lake.

Marine thraustochytrid: exploration from taxonomic challenges to biotechnological applications

Thraustochytrids, as a distinct group of heterotrophic protists, have garnered considerable attention owing to their remarkable adaptability in extreme marine environments, pronounced capacity for metabolic regulation and prolific production of high-value metabolites. The taxonomic classification of these microorganisms presents a substantial challenge due to the variability in morphological characteristics under different culture conditions. And this undermines the efficacy of traditional classification systems on physiological and biochemical traits. The establishment of a polyphasic taxonomic system integrating genomic characteristics in the future will provide new avenues for more accurate classification and identification. Thraustochytrids can effectively accumulate bioactive substances such as docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), squalene and carotenoids. Through fermentation optimization and genetic modification, scientists have significantly enhanced the production of these metabolites. Moreover, the application of thraustochytrids in aquaculture, poultry and livestock feed has significantly improved animal growth and physiological indicators meanwhile increasing their DHA content. Natural bioactive substances in thraustochytrids, such as terpenoid compounds with antioxidant properties, have been proposed for application in the cosmetics industry. In the field of pharmacology, thraustochytrids have shown certain anti-inflammatory and anti-cancer activities and provide potential for the development of new oral vaccines. Additionally, they can degrade various industrial and agricultural wastes for growth and fatty acid production, demonstrating their potential in environmental bioremediation. Therefore, thraustochytrids not only exhibit tremendous application potential in the field of biotechnology, but also hold significant value in environmental protection and commercialization.

Biodegradation of the strobilurin fungicide pyraclostrobin by Burkholderia sp. Pyr-1: Characteristics, degradation pathway, water remediation, and toxicity assessment

Pyraclostrobin, a widely used fungicide, poses significant risks to both the environment and human health. However, research on the microbial degradation process of pyraclostrobin was scarce. Here, a pyraclostrobin-degrading strain, identified as Burkholderia sp. Pyr-1, was isolated from activated sludge. Pyraclostrobin was efficiently degraded by strain Pyr-1, and completely eliminated within 6 d in the presence of glucose. Additionally, pyraclostrobin degradation was significantly enhanced by the addition of divalent metal cations (Mn2+ and Cu2+). The degradation pathway involving ether bond and N–O bond cleavage was proposed by metabolite identification. The sodium alginate-immobilized strain Pyr-1 had a higher pyraclostrobin removal rate from contaminated lake water than the free cells. Moreover, the toxicity evaluation demonstrated that the metabolite 1-(4-chlorophenyl)-1H-pyrazol-3-ol significantly more effectively inhibited Chlorella ellipsoidea than pyraclostrobin, while its degradation products by strain Pyr-1 alleviated the growth inhibition of C. ellipsoidea, which confirmed that the low-toxic metabolites were generated from pyraclostrobin by strain Pyr-1. The study provides a potential strain Pyr-1 for the bioremediation in pyraclostrobin-contaminated aquatic environments.

Biodegradation of a complex hydrocarbon mixture and biosurfactant production by Burkholderia thailandensis E264 and an adapted microbial consortium.

Bioremediation is considered to be an effective treatment for hydrocarbon removal from polluted soils. However, the effectiveness of this treatment is often limited by the low availability of targeted contaminants. Biosurfactants produced by some microorganisms can increase organic compound solubility and might then overcome this limitation. Two different inocula producers of biosurfactants (Burkholderia thailandensis E264 and SHEMS1 microbial consortium isolated from a hydrocarbon-contaminated soil) were incubated in Bushnell-Haas medium supplemented with hydrocarbons to investigate their biodegradation potential. Experimental results showed their ability to degrade 9.1 and 6.1% of hydrocarbons respectively after 65 days of incubation with an initial total hydrocarbon concentration of 16 g L-1. The biodegradation was more effective for the light and medium fractions (C10 to C36). B. thailandensis and SHEMS1 consortium produced surfactants after 14 days of culture during the stationary phase with hydrocarbons as the sole carbon and energy source. However, biosurfactant production did not appear to directly increase hydrocarbon degradation efficiency. The complexity and recalcitrance of hydrocarbon mixture used in this study appeared to continue to limit its biodegradation even in the presence of biosurfactants. In conclusion, B. thailandensis and SHEMS1 consortium can degrade recalcitrant hydrocarbon compounds and are therefore good candidates for the bioremediation of environments polluted by total hydrocarbons.

Characterization of the 3,4-Dichloroaniline Degradation Gene Cluster in Acinetobacter soli GFJ2.

3,4-Dichloroaniline (34DCA), a major metabolite of phenylurea herbicides, causes environmental contamination owing to its toxicity and recalcitrant properties. Acinetobacter soli strain GFJ2, isolated from soil potentially contaminated with herbicides, can degrade 34DCA. This study aimed to identify and characterize the 34DCA degradation gene cluster responsible for the conversion of 34DCA to 4,5-dichlorocatechol in the strain GFJ2. Genome analysis revealed one chromosome and seven plasmids in GFJ2, comprising 21, 75, and 3309 copies of rRNA, 75 tRNA, and protein-encoding genes, respectively. A gene cluster responsible for 34DCA degradation was identified, comprising dcdA, dcdB, and dcdC, which encode dioxygenase, flavin reductase, and aldehyde dehydrogenase, respectively. Transcriptional analysis indicated that this gene cluster is constructed as an operon, induced during 34DCA utilization. The heterologous expression of dcdA and dcdB in Escherichia coli confirmed their activity in degrading 34DCA to an intermediate metabolite, converted to 4,5-dichlorocatechol via a reaction involving the dcdC gene product, suggesting their involvement in 34DCA conversion to 4,5-dichlorocatechol. Deletion mutants of dcdA and dcdB lost 34DCA degradation ability, confirming their importance in 34DCA utilization in GFJ2. This study provides insights into the genetic mechanisms of 34DCA degradation by GFJ2, with potential applications in the bioremediation of environments contaminated by phenylurea herbicides.

Bioaccumulation of molybdate ions by alkanotrophic Rhodococcus leads to significant alterations in cellular ultrastructure and physiology

Alkanotrophic Rhodococcus strains from the Regional Specialised Collection of Alkanotrophic Microorganisms (acronym IEGM, www.iegmcol.ru) were screened for accumulation and sorption of MoO42- ions. Morphological and ultrastructural changes observed in bacterial cells during their cultivation in the molybdenum-containing medium are described. The species peculiarities, growth substrate preferences, and other physiological features allowing for the efficient removal of molybdate ions from the culture medium are discussed. Bioinformatics analysis of genes and proteins responsible for resistance to and accumulation of molybdenum was carried out using the sequenced R. ruber IEGM 231 and other published Rhodococcus genomes. n-Hexadecane growing strains with high (up to 85 %) accumulative activity and resistance to elevated (up to 20.0 mM) molybdenum concentrations were selected, which can be used for bioremediation of environments co-contaminated with heavy metals and hydrocarbons. Transmission electron microscopy and energy dispersive X-ray spectroscopy (TEM-EDX) revealed the ability of Rhodococcus not only to accumulate, but also to chemically convert soluble toxic molybdenum into insoluble compounds detected in the form of electron-dense nanoparticles.

Safety attributes of Pseudomonas sp. P26, an environmental microorganism with potential application in contaminated environments

Currently, the selection of non-pathogenic microorganisms that lack clinically relevant antimicrobial resistance is crucial to bioaugmentation strategies. Pseudomonas sp. P26 (P26) is an environmental bacterium of interest due to its ability to remove aromatic compounds from petroleum, but its safety characteristics are still unknown. The study aimed to: a) determine P26 sensitivity to antimicrobials, b) investigate the presence of quinolone and β-lactam resistance genes, c) determine the presence of virulence factors, and d) evaluate the effect of P26 on the viability of Galleria mellonella (an invertebrate animal model). P26 antimicrobial sensitivity was determined in vitro using the Kirby-Bauer agar diffusion method and the VITEK 2 automated system (BioMerieux®). Polymerase Chain Reaction was employed for the investigation of genes associated with quinolone resistance, extended-spectrum β-lactamases, and carbapenemases. Hemolysin and protease production was determined in human blood agar and skimmed-milk agar, respectively. In the in vivo assay, different doses of P26 were injected into Galleria mellonella larvae and their survival was monitored daily. Control larvae injected with Pseudomonas putida KT2440 (a strain considered as safe) and Pseudomonas aeruginosa PA14 (a pathogenic strain) were included. Pseudomonas sp. P26 was susceptible to most evaluated antimicrobials, except for trimethoprim-sulfamethoxazole. No epidemiologically relevant genes associated with quinolone and β-lactam resistance were identified. Hemolysin and protease production was only evidenced in the virulent strain (PA14). Furthermore, the results obtained in the in vivo experiment demonstrated that inocula less than 108 CFU/mL of P26 and P. putida KT2440 did not significantly affect larval survival, whereas larvae injected with the lowest dose of the pathogenic strain P. aeruginosa PA14 experienced instant mortality. The results suggest that Pseudomonas sp. P26 is a safe strain for its application in environmental bioremediation processes. Additional studies will be conducted to ensure the safety of this bacterium against other organisms.

Isolation, identification and whole-genome analysis of an Achromobacter strain with a novel sulfamethazine resistance gene and sulfamethazine degradation gene cluster

A sulfamethazine (SM2) degrading strain, Achromobacter mucicolens JD417, was isolated from sulfonamide-contaminated sludge using gradient acclimation. Optimal SM2 degradation conditions were pH 7, 36 °C, and 5 % inoculum, achieving a theoretical maximum degradation rate of 48 % at 50 ppm SM2. Cell growth followed the Haldane equation across different SM2 concentrations. Whole-genome sequencing of the strain revealed novel functional annotations, including a sulfonamide resistance gene (sul4) encoding dihydropteroate synthase, two flavin-dependent monooxygenase genes (sadA and sadB) crucial for SM2 degradation, and unique genomic islands related to metabolism, pathogenicity, and resistance. Comparative genomics analysis showed good collinearity and homology with other Achromobacter species exhibiting organics resistance or degradation capabilities. This study reveals the novel molecular resistance and degradation mechanisms and genetic evolution of an SM2-degrading strain, providing insights into the bioremediation of sulfonamide-contaminated environments.

The unique biodegradation pathway of benzo[a]pyrene in moderately halophilic Pontibacillus chungwhensis HN14

Benzo[a]pyrene (BaP), as the typical representative of polycyclic aromatic hydrocarbons (PAHs), is a serious hazard to human health and natural environments. Though the study of microbial degradation of PAHs has persisted for decades, the degradation pathway of BaP is still unclear. Previously, Pontibacillus chungwhensis HN14 was isolated from high salinity environment exhibiting a high BaP degradation ability. Here, based on the intermediates identified, BaP was found to be transformed to 4,5-epoxide-BaP, BaP-trans-4,5-dihydrodiol, 1,2-dihydroxy-phenanthrene, 2-carboxy-1-naphthol, and 4,5-dimethoxybenzo[a]pyrene by the strain HN14. Furthermore, functional genes involved in degradation of BaP were identified using genome and transcriptome data. Heterogeneous co-expression of monooxygenase CYP102(HN14) and epoxide hydrolase EH(HN14) suggested that CYP102(HN14) could transform BaP to 4,5-epoxide-BaP, which was further transformed to BaP-trans-4,5-dihydrodiol by EH(HN14). Moreover, gene cyp102(HN14) knockout was performed using CRISPR/Cas9 gene-editing system which confirmed that CYP102(HN14) play a key role in the initial conversion of BaP. Finally, a novel BaP degradation pathway was constructed in bacteria, which showed BaP could be converted into chrysene, phenanthrene, naphthalene pathways for the first time. These findings enhanced our understanding of microbial degradation process for BaP and suggested the potential of using P. chungwhensis HN14 for bioremediation in PAH-contaminated environments.

Streptomycetes as Microbial Cell Factories for the Biotechnological Production of Melanin.

Melanins are complex, polymeric pigments with interesting properties like UV-light absorbance ability, metal ion chelation capacity, antimicrobial action, redox behaviors, and scavenging properties. Based on these characteristics, melanins might be applied in different industrial fields like food packaging, environmental bioremediation, and bioelectronic fields. The actual melanin manufacturing process is not environmentally friendly as it is based on extraction and purification from cuttlefish. Synthetic melanin is available on the market, but it is more expensive than animal-sourced pigment and it requires long chemical procedures. The biotechnological production of microbial melanin, instead, might be a valid alternative. Streptomycetes synthesize melanins as pigments and as extracellular products. In this review, the melanin biotechnological production processes by different Streptomyces strains have been revised according to papers in the literature. The different fermentation strategies to increase melanin production such as the optimization of growth conditions and medium composition or the use of raw sources as growth substrates are here described. Diverse downstream purification processes are also reported as well as all the different analytical methods used to characterize the melanin produced by Streptomyces strains before its application in different fields.

Arsenic effectively improves the degradation of fluorene by Rhodococcus sp. 2021 under the combined pollution of arsenic and fluorene

The performance of bacterial strains in executing degradative functions under the coexistence of heavy metals/heavy metal-like elements and organic contaminants is understudied. In this study, we isolated a fluorene-degrading bacterium, highly arsenic-resistant, designated as strain 2021, from contaminated soil at the abandoned site of an old coking plant. It was identified as a member of the genus Rhodococcus sp. strain 2021 exhibited efficient fluorene-degrading ability under optimal conditions of 400 mg/L fluorene, 30 °C, pH 7.0, and 250 mg/L trivalent arsenic. It was noted that the addition of arsenic could promote the growth of strain 2021 and improve the degradation of fluorene – a phenomenon that has not been described yet. The results further indicated that strain 2021 can oxidize As3+ to As5+; here, approximately 13.1% of As3+ was converted to As5+ after aerobic cultivation for 8 days at 30 °C. The addition of arsenic could greatly up-regulate the expression of arsR/A/B/C/D and pcaG/H gene clusters involved in arsenic resistance and aromatic hydrocarbon degradation; it also aided in maintaining the continuously high expression of cstA that codes for carbon starvation protein and prmA/B that codes for monooxygenase. These results suggest that strain 2021 holds great potential for the bioremediation of environments contaminated by a combination of arsenic and polycyclic aromatic hydrocarbons. This study provides new insights into the interactions among microbes, as well as inorganic and organic pollutants.

Multi-omics insights into biogeochemical responses to organic matter addition in an acidic pit lake: Implications for bioremediation

Acidic pit lakes (APLs) emerge as reservoirs of acid mine drainage in flooded open-pit mines, representing extreme ecosystems and environmental challenges worldwide. The bioremediation of these oligotrophic waters necessitates the addition of organic matter, but the biogeochemical response of APLs to exogenous organic matter remains inadequately comprehended. This study delves into the biogeochemical impacts and remediation effects of digestate-derived organic matter within an APL, employing a multi-omics approach encompassing geochemical analyses, amplicon and metagenome sequencing, and ultra-high resolution mass spectrometry. The results indicated that digestate addition first stimulated fungal proliferation, particularly Ascomycetes and Basidiomycetes, which generated organic acids through lignocellulosic hydrolysis and fermentation. These simple compounds further supported heterotrophic growth, including Acidiphilium, Acidithrix, and Clostridium, thereby facilitating nitrate, iron, and sulfate reduction linked with acidity consumption. Nutrients derived from digestate also promoted the macroscopic development of acidophilic algae. Notably, the increased sulfate reduction-related genes primarily originated from assimilatory metabolism, thus connecting sulfate decrease to organosulfur increase. Assimilatory and dissimilatory sulfate reduction collectively contributed to sulfate removal and metal fixation. These findings yield multi-omics insights into APL biogeochemical responses to organic matter addition, enhancing the understanding of carbon-centered biogeochemical cycling in extreme ecosystems and guiding organic amendment-based bioremediation in oligotrophic polluted environments.

Biotransformation of roxarsone by earthworms and subsequent risk of soil arsenic release: The role of gut bacteria

The organoarsenical feed additive roxarsone (ROX) is a ubiquitous threat due to the unpredictable levels of arsenic (As) released by soil bacteria. The earthworms representing soil fauna communities provide hotspots for As biotransformation genes (ABGs). Nonetheless, the role of gut bacteria in this regard is unclear. In this study, the changes in As speciation, bacterial ABGs, and communities were analyzed in a ROX-contaminated soil (50 mg/kg As in ROX form) containing the earthworm Eisenia feotida. (RE vs. R treatment). After 56 d, earthworms reduced the levels of both ROX and total As by 59 % and 17 %, respectively. The available As content was 10 % lower in the RE than in R treatment. Under ROX stress, the total ABG abundance was upregulated in both earthworm gut and soil, with synergistic effects observed following RE treatment. Besides, the enrichment of arsM and arsB genes in earthworm gut suggested that gut bacteria may facilitate As removal by enhancing As methylation and transport function in soil. However, the bacteria carrying ABGs were not associated with the ABG abundance in earthworm gut indicating the unique strategies of earthworm gut bacteria compared with soil bacteria due to different microenvironments. Based on a well-fit structural equation model (P = 0.120), we concluded that gut bacteria indirectly contribute to ROX transformation and As detoxification by modifying soil ABGs. The positive findings of earthworm-induced ROX transformation shed light on the role of As biomonitoring and bioremediation in organoarsenical-contaminated environments.

A 2,2-dichloropropionic acid-degrading novel Pseudomonas fluorescence strain fatsa001: isolation, identification, and characterization

There are mounting concerns over the high concentrations of non-biogenic, toxic halogenated organic compounds being liberated into the ecosystem. Therefore, this study’s isolation of a novel bacterium from a contaminated stream in Fatsa, Ordu, Turkey, adept in degrading 2,2-dichloropropionic (of 2,2-DCP) is a welcome endeavor. The ability of the bacterial isolate to utilize 2,2-DCP as the sole carbon and energy source was discovered when the bacterium was observed to grow well on liquid minimal media containing 20 mM of 2,2-DCP, showing a doubling time of 14.2 h. The following genetic and biochemical characterizations revealed that the 16S rRNA sequence of the fatsa001strain is identical (99%) to Pseudomonas fluorescence, after which the sequence was deposited in the NCBI GenBank as Pseudomonas sp. strain fatsa001 (MN098848). The halogen-degrading ability of the P. fluorescens fatsa001 bacterium was again confirmed by the PCR data, which showed the presence of a conserved group of amino acids from the group I dehalogenase gene. It worth mentioning here that this is the first report on a P. fluorescence bacterial strain with the ability to degrade toxic 2,2-DCP. The detoxification ability of this bacterium envisages its practicality as an in situ environmental bioremediation agent.

Efficient bio-remediation of multiple aromatic hydrocarbons using different types of thermotolerant, ring-cleaving dioxygenases derived from Aeribacillus pallidus HB-1

As toxic contaminants, aromatic compounds are widespread in most environmental matrices, and bioenzymatic catalysis plays a critical role in the degradation of xenobiotics. Here, a thermophillic aromatic hydrocarbon degrader Aeribacillus pallidus HB-1 was found. Bioinformatic analysis of the HB-1 genome revealed two ring-cleaving extradiol dioxygenases (EDOs), among which, EDO-0418 was assigned to a new subfamily of type I.1 EDOs and exhibited a broad substrate specificity, particularly towards biarylic substrate. Both EDOs exhibited optimal activities at elevated temperatures (55 and 65 °C, respectively) and showed remarkable thermostability, pH stability, metal ion resistance and tolerance to chemical reagents. Most importantly, simulated wastewater bioreactor experiments demonstrated efficient and uniform degradation performance of mixed aromatic substrates under harsh environments by the two enzymes combined for potential industrial applications. The unveiling of two thermostable dioxygenases with broad substrate specificities and stress tolerance provides a novel approach for highly efficient environmental bioremediation using composite enzyme systems.

Isolation and Influence of Carbon Source on the Production of Extracellular Polymeric Substance by Bacteria for the Bioremediation of Heavy Metals in Santo Amaro City

The city of Santo Amaro (Bahia, Brazil) gained visibility among the scientific community due to the contamination of the Subaé River by lead and cadmium from the PLUMBUM Mineração e Metalurgia Ltda industry, on the banks of the river in 1956, which produced lead ingots The present work aimed to investigate the adsorption capacity of heavy metals (Pb and Cd) of EPS produced by bacterial species from the Subaé River, for possible future application of these biopolymers in bioremediation processes in areas impacted by the aforementioned heavy metals. Subaé river water was collected for physical-chemical analysis and bacterial isolation. It was verified that all isolated bacteria produced an expressive amount of Exopolysaccharide (EPS). Thus, the optimization of this production in different sugars (sucrose, glucose, and mannitol) and in three different pHs: 5.5; 6.5, and 7.5. All bacteria produced EPS in large quantities and the best sugar was sucrose at pH 7.5. In order to use the EPS for the bioremediation area, the adsorption test of lead and cadmium was carried out by the isolated EPS. 0.5 g of the EPS was dissolved in 50 ml of deionized water, then the solutions of metals, lead acetate, and cadmium sulfate (procedure performed separately) were incubated at 28 °C for 16 h after that period, and were centrifuged. Samples were filtered to separate the insoluble EPS and the filtrates obtained were used in the quantification of the metals by atomic absorption (FAAS- Flame Atomic Absorption Spectrometry). Bacillus spp., Bacillus cereus, Staphylococcus spp., and Serratiamarcescens, all showed tolerance to the tested metals, due to the efficiency in the adsorption capacity of the EPS, and it was possible to distinguish seven genera, Klebsiella pneumonia, Pseudomonas aeruginosa, Lysinibacillus spp. to be used in the bioremediation of environments contaminated with heavy metals.

High-throughput analysis using 16S rRNA sequencing of bacterial communities associated in selected mangrove species from Bayug Island, Iligan City, Philippines

Abstract. Siblos SKV, Tabugo SR. 2023. High-throughput analysis using 16S rRNA sequencing of bacterial communities associated in selected mangrove species from Bayug Island, Iligan City, Philippines. Biodiversitas 25: 53-61. Mangrove ecosystems are recognized globally as highly productive ecosystems, that play a crucial role in carbon sequestration, erosion control, water purification, and as essential breeding grounds for diverse aquatic life. They also offer specialized ecological niches, accommodating a diverse range of organisms, including bacterial communities. This study aimed to investigate bacterial communities of Bayug Island in Iligan City, Philippines, inhabiting six mangrove species, namely Rhizophora stylosa Griffith, Rhizophora apiculata Blume, Rhizophora mucronata Lam., Sonneratia alba Sm., Ceriops tagal (Perr.) C.B.Rob., and Nypa fruticans Wurmb and their possible functions within the mangrove forests. Genomic DNA was extracted from the six pooled soil samples, and the V3-V4 region of the 16S rRNA gene was sequenced using the Illumina MiSeq platform. Six amplicon libraries, corresponding to the mangrove species were analyzed with Parallel Meta Suite software, yielding 173,270 amplicon sequence variants (ASVs) after quality control. The study identified the top five most abundant ASVs in the mangrove rhizosphere, linked to the genera Vibrio, Stenotrophomonas, Serratia, Pseudoalteromonas, and Achromobacter. Among the mangrove species, S. alba exhibited higher alpha diversity according to the Shannon index. PICRUSt analysis revealed that microorganisms are involved in biodegradation, xenobiotic metabolism, and other metabolic processes within the mangroves. These bacteria could find applications in environmental cleanup, bioremediation, waste treatment, and soil health improvement. This result contributes to the ongoing ecological restoration of mangrove forests at the research site.

Azolla Plant Production and Their Potential Applications

Globally, the human population is growing at an alarming rate, reducing land coverage over time. In the modern world, lifestyle changes, the nature of work, and food habits increase the incidence of serious diseases in animals, and human activity influences the environment, such as the use of chemical fertilizers for agriculture, large terrestrial ecosystems all over the biosphere, such as deforestation of plants, which could not sink from atmospheric CO2, and the production of fuels for energy, which would increase the need for fossil fuels but would also deliver low energy fuels at a high energy cost. To overcome the above problems, Azolla plants perform well since they can be grown at low labor costs, on small plots of land, and for a variety of purposes including animal feed/livestock, poultry and fish production, environmental remediation, biofertilizer and biocontrol for mosquito repellents, carbon sequestration of CO2, and bioenergy effectiveness all year. As a result of their low impact on the environment and human health, Azolla plants are becoming increasingly important. The purpose of this review is to provide evidence of Azolla plant production and its potential role in various applications for a greener, more sustainable approach. This review was progressive in that it assessed and produced peer-reviewed papers related to Azolla plant production and its potential role in different applications for a sustainable greener approach. Based on the findings of reputable educational journals, articles were divided into three categories: methods used to produce the nutritional composition of Azolla, environmental factors that affect the efficiency of Azolla plants, and strain improvement of Azolla for enhanced multipurposes and techniques that are currently being used to meet Azolla plants production and its prospective applications for different sustainable greener approaches. The present findings indicate that Azolla is a rich source of protein, which has a clear benefit in offsetting a portion of the nutritional needs of animal/livestock, poultry, and fish production with what is effectively a low-cost dietary supplement, biocontrol of mosquito repellent, environmental bioremediation, biofertilizer, carbon sequester of CO2, and bioenergy for the potential need of Azolla plant applications. Azolla plants have long been recognized for their benefits in greener and more sustainable lifestyles, as well as quality enhancement and bio-based economy over traditional approaches. Because it relied on natural resources and utility green production, this review’s recovery was chosen as an appropriate and environmentally sound solution for a long and healthy lifestyle.

Assessment of the potentials of Autochthonous lipase-producing bacteria in the treatment of palm oil mill effluent

Pollution caused by the release of untreated palm oil mill effluent (POME) is a major environmental concern. This research assessed the potentials of single and consortium ofautochthonous lipase-producing bacteria as a non-invasive procedure in the biotreatment ofPOME. The identity of lipase-producing bacteria in POME were determined using morphological and biochemical techniques. Identified isolates were monitored for POME utilization by measurement of optical density at 600 nm in 25 ml Bushnell Haas broth supplemented with 0.25 ml sterilized POME. Individual isolates and consortium were then used for the bioremediation of POME. Quality parameters including pH, total suspended solid (TSS), oil and grease, chemical oxygen demand (COD), biological oxygen demand (BOD), total organic carbon (TOC), total organic matter (TOM) and total nitrogen (TN) of the raw and treated effluents were evaluated. The population (CFU/ml) of total heterotrophic, POME - utilizing and lipolytic bacteria were 3.9 x 106, 2.8 x 106 and 3.5 x 105 respectively. The lipolytic bacterial isolates include Brenneria nigrifluens, Bacillus circulans and Paenibacillus pectinilyticus. Results revealed varying pH of 5.03 and 6.81 - 7.26 for untreated and treated respectively. The lipolytic bacteria from POME caused reduction efficiency of 100% in TSS and oil and grease contents of the treated effluents relative to the raw samples. The COD, BOD, TOC, TOM and TN reduction ranged 17.90 - 93.55, 1.66 - 90.52, 16.34 - 59.79 %, 6.18 - 80.78 % and 11.71 - 93.66 % respectively. This research indicated that POME indigenous lipase-producing bacteria improved POME quality and therefore suggestive of their potentials in the bioremediation of POME-contaminated environment with the consortium being most effective.

Isolation and characterization of Candida tropicalis B: a promising yeast strain for biodegradation of petroleum oil in marine environments

The increasing interest in environmental protection laws has compelled companies to regulate the disposal of waste organic materials. Despite efforts to explore alternative energy sources, the world remains heavily dependent on crude petroleum oil and its derivatives. The expansion of the petroleum industry has significant implications for human and environmental well-being. Bioremediation, employing living microorganisms, presents a promising approach to mitigate the harmful effects of organic hydrocarbons derived from petroleum. This study aimed to isolate and purify local yeast strains from oil-contaminated marine water samples capable of aerobically degrading crude petroleum oils and utilizing them as sole carbon and energy sources. One yeast strain (isolate B) identified as Candida tropicalis demonstrated high potential for biodegrading petroleum oil in seawater. Physiological characterization revealed the strain’s ability to thrive across a wide pH range (4–11) with optimal growth at pH 4, as well as tolerate salt concentrations ranging from 1 to 12%. The presence of glucose and yeast extract in the growth medium significantly enhanced the strain's biomass formation and biodegradation capacity. Scanning electron microscopy indicated that the yeast cell diameter varied based on the medium composition, further emphasizing the importance of organic nitrogenous sources for initial growth. Furthermore, the yeast strain exhibited remarkable capabilities in degrading various aliphatic and aromatic hydrocarbons, with a notable preference for naphthalene and phenol at 500 and 1000 mg/l, naphthalene removal reached 97.4% and 98.6%, and phenol removal reached 79.48% and 52.79%, respectively. Optimization experiments using multi-factorial sequential designs highlighted the influential role of oil concentration on the bioremediation efficiency of Candida tropicalis strain B. Moreover, immobilized yeast cells on thin wood chips demonstrated enhanced crude oil degradation compared to thick wood chips, likely due to increased surface area for cell attachment. These findings contribute to our understanding of the potential of Candida tropicalis for petroleum oil bioremediation in marine environments, paving the way for sustainable approaches to address oil pollution.