Minimal Salt Research Articles

Understanding the tolerance of halophilic archaea to stress landscapes.

Haloarchaea, known for their resilience to environmental fluctuations, require a minimum salt concentration of 10% (w/v) for growth and can survive up to 35% (w/v) salinity. In biotechnology, these halophiles have diverse industrial applications. This study investigates the tolerance responses of nine haloarchaea: Haloferax mediterranei, Haloferax volcanii, Haloferax gibbonsii, Halorubrum californiense, Halorubrum litoreum, Natrinema pellirubrum, Natrinema altunense, Haloterrigena thermotolerans and Haloarcula sinaiiensis, under various stressful conditions. All these archaea demonstrated the ability to thrive in the presence of toxic metals such as chromium, nickel, cobalt and arsenic, and their tolerance to significantly elevated lithium concentrations in the medium was remarkable. Among the studied haloarchaea, Hfx. mediterranei exhibited superior resilience, particularly against lithium, with an impressive minimum inhibitory concentration (MIC) of up to 4 M LiCl, even replacing NaCl entirely. Haloferax species showed specificity for conditions with maximal growth rates, while Htg. thermotolerans and Nnm. altunense displayed high resilience without losing growth throughout the ranges, although these were generally low. ICP-MS results highlighted the impressive intracellular lithium accumulation in Nnm. pellirubrum, emphasizing its potential significance in bioremediation. This research highlights a new characteristic of haloarchaea, their tolerance to high lithium concentrations and the potential for new applications in extreme industrial processes and bioremediation.

Biodegradation of Polyethylene Using Bacillus tropicus Isolated from Sewage Wastewater Treatment Plant

One of the most pressing environmental problems contemporary civilizations confront is the ever-increasing amount of plastic waste. Because of their impact on every living thing, these wastes are seen as a major issue on a global scale. To counteract the harmful environmental effects caused by conventional disposal methods, it is critical to show that eco-friendly alternatives are viable. Biodegradation is one of the best eco-friendly methods for removing plastic waste. In this study, we aimed to identify bacteria from sewage wastewater treatment plants (SWWs) that could degrade low-density polyethylene (LDPE). Bacterial strains isolated from sewerage wastewater were incubated for 120 days in 50 mL of minimal salt media (MSM) containing 60 mg of low-density polyethylene (LDPE). After four months, our research revealed that Bacillus tropicus (SH4) demonstrated significant potential, degrading the LDPE up to 21.6%. We observed the changes after biodegradation using FTIR, GC-MS, and SEM analysis. In conclusion, microorganisms extracted from sewage wastewater possess the ability to mitigate plastic contamination in aquatic ecosystems. Future proteomics and genome investigations are necessary to elucidate the enzymes and metabolic processes implicated in plastic breakdown.

Can Front-of-Pack Labeling Encourage Food Reformulation? A Cross-Sectional Study on Packaged Bread.

Front-of-pack labeling (FOPL) may represent an important instrument for the food industry in the promotion of food product reformulation. The present cross-sectional study used salt reduction in packaged breads as a case study, aiming to investigate whether two different types of FOPL (i.e., Nutri-Score (NS) and NutrInform battery (NIB)) can capture food reformulation and thus be effective tools for encouraging reformulation. The Nutri-Score and NIB were calculated by consulting the nutritional declarations and ingredient lists of 527 packaged breads currently sold in Italy before and after applying three different theoretical reformulation strategies: (i) a 25% salt decrease from the current median salt content in bread; (ii) a reduction of up to 0.825 g/100 g of salt, corresponding to the sodium benchmark of 330 mg/100 g set by the World Health Organization (WHO); and (iii) the minimum salt reduction needed to improve the NS by one grade. The results show that only ~44% of breads had improved NSs when the sodium was lowered to reach the WHO benchmark or when salt was reduced by 25%, whereas large variability was observed in the minimum salt reduction needed to improve the NS. Regarding the NIB, the battery for salt improved when both strategies of reformulation were applied. FOPL is not always effective in capturing food reformulation in terms of salt reduction, possibly discouraging the efforts of food companies to improve the nutritional quality of foods.

Long-term Outcome of a Chihuahua With Idiopathic Syndrome of Inappropriate Antidiuretic Hormone Secretion.

An approximately 3 yr old female Chihuahua was presented for evaluation of polyuria and polydipsia noted by the owner after adoption. Serum biochemistry and urinalysis revealed hyponatremia, hypochloremia, hypo-osmolality, and normal fractional excretion of sodium. Serum antidiuretic hormone concentration was 5.54 pg/mL and serum copeptin concentration was 135.40 pg/mL. The antidiuretic hormone value was above the reported range for healthy dogs and was considered inappropriate in light of serum osmolality. Idiopathic syndrome of inappropriate antidiuretic hormone secretion was considered the most likely diagnosis after excluding other potential causes, such as diuretic use, renal disease, adrenal disease, and thyroid dysfunction. The dog remains clinically well 2 yr after diagnosis without specific treatment other than minimal dietary salt supplementation. This case is unique because of the absence of systemic or neurologic signs, good long-term outcome without treatment, and use of novel diagnostic testing.

Biological decolorisation of the anionic Dye Acid Blue 9 by bacterial consortium: A sustainable and ecofriendly approach for the treatment of textile wastewater

Industrialization has led to the proliferation of dye waste, posing significant environmental challenges due to the structural complexity of dyes. Various industries discharge untreated toxic waste into water bodies, posing severe environmental hazards to humans as well as aquatic ecosystem. Synthetic dyes from textiles exacerbate this issue due to their toxicity, making the management of industrial wastewater a significant environmental challenge. This study offers a potential solution by investigating the degradation of hazardous Acid Blue-9 (AB9) dye using bacterial consortium containing Pseudomonas fluorescens and Bacillus subtilis. The experiments were conducted in minimal salt media with varying concentrations of different parameters (pH, temperature, initial dye concentration, size of inoculum, carbon and nitrogen sources) used for optimization process. Using the One-Factor-At-A-Time method, the consortium in the study was able to decolorize at a noteworthy rate of decolorisation about 85–87.2 %. This rate was notably increased to around 90.02 % with the implementation of Response Surface Methodology. Additionally, the decolorisation process was further confirmed by using UV-Visible Spectroscopy and Fourier Transform InfraRed Spectroscopy. Additionally, a phytotoxicity assessment test on crops of agricultural significance supports the potential of this bacterial consortium for the bioremediation of AB9 contaminated water. The dye samples treated with bacterial consortium showed significantly higher seed germination rates (∼82.9 %), along with increased shoot (∼9.13 cm) and root lengths(∼3.01 cm), compared to the untreated samples. This promising finding suggests the potential for reusing treated water in agriculture and industry, offering a sustainable solution to water pollution.

Virulence factors associated with hyper virulent Klebsiella pneumoniae isolated from Different Clinical Sources

Klebsiella pneumonia is an opportunity pathogen causing several diseases including sepsis, pneumonia and wound infections. There are two pathotypes of Klebsiella pneumonia: classical K. pneumoniae (cKp) and hypervirulent K. pneumonia (hvkp). In this study, we attempted to discover the extent occurrence of hypervirulent K. pneumoniae strains among patients in Kirkuk city and their virulence factors. A total of 150 samples were collected from different hospitals in Kirkuk city (Kirkuk General Hospital, Azadi Teaching Hospital, Gynecological and Pediatric (Al-Nasr) Hospital and Children Hospital) during the period between November 2021 to June 2022. The age of patients ranged between 20- 60 years with both sexes. The results showed that 23.33% of K. pneumoniae isolates were positive for string test. Similar results were obtained by using sedimentation assay. The capsule of hvKp is a key virulence factor aiding in the bacterial dissemination and infection. For this reason, in current study, the capsular polysaccharide (CPS) was extracted and quantified. The results showed excessive production of capsular polysaccharide as seen in Klebsiella isolates 16,22,23,24,25,26,28 with an amount 49,41,50,74,49,49,73 μg/ml of CPS respectively. Siderophore production was also examined by using M9 minimal salts media. The results revealed that all K. pneumoniae isolates (100%) were able to produce siderophore. In addition, resistance to tellurite was also identified by using tellurite containing selective media and the results showed that 50% of isolates were resistant to tellurite and the remaining 50% were susceptible. A molecular study using conventional PCR revealed that 21 out of 30 isolates (70%) harbored the rmpA gene while the remaining 9 isolates (30%) lacked this gene. The presence of the iucA virulence gene was also detected and found to be present in all the isolates. Additionally, our findings indicated that 7 out of the 30 isolates (23%) were classified as hvkp.

Isolation and Identification of Tannin-Degrading Bacteria From Goat Feces, Ruminal Fluid, and Rumen Gut

Tannins are toxic polyphenols present in various plants, contributing to microbial attacks and plant protection due to their astringence and bitter taste. However, high tannin inclusion in poultry diets will result in dyspepsia, hampering nutrient absorption and digestion. Interestingly, several bacteria occupying the rumen and gastrointestinal tract (GIT) of animals may tolerate tannins and degrade them by wielding tannase enzymes. The study aims to isolate and characterize potential tannin-degrading bacteria (TDB) from several ruminant specimens. The TDBs were isolated based on their tannin hydrolyzing ability on a minimal salt medium (MSM) agar complemented with 0.2% tannic acid as the sole source of carbon and energy. The maximum tannin tolerance of the isolates was characterized using increased tannin concentrations on the MSM agar plates. Furthermore, the tannase activity was also evaluated over a five-day incubation. A total of 42 tannin degraders were isolated, and 10 TDBs were chosen for further characterization based on the hydrolyzed zone produced. Molecular identification revealed the presence of Bacillus cereus (TDB536), Lysinibacillus macroides (TDB17), Acinetobacter nosocomialis (TDB18, 20, 23, 24, 30, 35), and Staphylococcus saprophyticus (TDB40). TDB17, TDB18, and TDB24 showed the highest tannic acid tolerance at 1.0%, while TDB36 and TDB40 exhibited the lowest tolerance at 0.4%. Each TDB displayed varying tannase activities, ranging from 11.56 to 42.08 U/mL over a five-day incubation period. TDB5 and TDB35 demonstrated significantly higher tannase activity on day 2 (p<0.05). Meanwhile, TDB23 and TDB24 showed the highest tannase on day 4 (p<0.05). Among the isolates, A. nosocomialis strain AE6 (TDB24) from feces exhibited the highest tannase activity (42.08 U/mL) and represented the best TDB. The isolated strains demonstrate their capabilities in reducing tannin's antinutritional effects in poultry feed.

Purification of biodiesel-derived crude glycerol and its application in plasticizing cassava starch bioplastics

This study focused on purifying crude glycerol, a by-product of biodiesel production, using acid-precipitation, methanol extraction, and adsorption with acid-activated charcoal. Among the acids tested—sulfuric, phosphoric, and hydrochloric—phosphoric acid proved most effective, producing the clearest glycerol with minimal salt deposition. The purified glycerol was then used to produce bioplastics, which were tested for mechanical properties. The results indicated that Phosphoric acid yielded the clearest glycerol with minimal salt deposition. The resultant salt, potassium phosphate (K2PO4), has potential as a fertilizer. The purified glycerol showed increased density and viscosity, indicating higher purity compared to crude glycerol. The density of the purified glycerol was closer to that of analytical-grade glycerol. Bioplastic 1 (using analytical-grade glycerol) exhibited the highest tensile strength, withstanding up to 4.3N and extending about 104mm before breaking. Bioplastic 2 (using glycerol purified with hydrochloric acid) withstood up to 4.1N, while Bioplastic 3 (using glycerol purified with acetic acid) endured the least stress, withstanding up to 3.8N and extending up to 87mm before breaking. The study demonstrates that phosphoric acid is an effective agent for purifying crude glycerol, significantly enhancing its quality. The purified glycerol, in turn, improves the mechanical properties of bioplastics, making them more durable and suitable for a range of applications. This process not only adds value to the biodiesel production by-product but also contributes to the development of stronger, more versatile bioplastics.

A Review on the Optimization of Irrigation Schedules for Farmlands Based on a Simulation–Optimization Model

Agriculture is the most important sector that is consuming water resources. In the context of global water scarcity, how to use limited water resources to improve water use efficiency in agriculture or achieve maximum crop yield and fruit quality is of great significance for ensuring food and water security. Optimizing irrigation schedules is an effective measure to improve water use efficiency, where crop models also play an important role. However, there is little research summarizing the optimization of irrigation schedules based on crop models. This study provides a systematic review on how to optimize irrigation schedules based on crop models and simulation–optimization models. When optimizing irrigation schedules based on crop models, the selected models are usually mechanistic agro-hydrological models. Irrigation scenarios and optimization objectives are mainly focused on both crop and water aspects, such as maximizing crop yield, fruit quality, water productivity, and irrigation water productivity. Minimizing crop water consumption and total irrigation amounts serve as optimization objectives, and irrigation quantity, irrigation frequency, and irrigation interval serve as decision variables. In saline areas or low fertilizer utilization areas, the optimization objectives and decision variables also involve some indicators related to salt and nitrogen, such as the maximum desalination rate, minimum salt content, fertilizer utilization efficiency, nitrogen fertilizer productivity, nitrogen fertilizer utilization efficiency, nitrogen leaching rate, which serve as the optimization objectives, and the irrigation water salinity, or fertilization schedules serve as the decision variables. When optimizing irrigation schedules based on simulation–optimization models, the models have mainly been upgraded from water-production function to crop mechanism models. In addition, optimization algorithms have been upgraded from traditional optimization techniques to intelligent optimization algorithms. Decision-making techniques are used to make decisions on optimization results. In addition, the spatial scale for the optimization problem of irrigation schedules was developed from fields to regions, and the time scale was developed from the growth stage, beginning with months, and shortening to ten days, then to a day, and then to an hour. This study also provides a detailed introduction to widely used optimization algorithms, such as genetic algorithms, as well as decision techniques. At the same time, it is proposed that the future should focus on improving crop models and analyzing uncertainty in research on irrigation schedule optimization, which is of great significance for the precise regulation of irrigation schedules.

Isolation of Monocrotophos degrading bacterial consortium from agricultural soil for in vivo analysis of pesticide degradation.

Extensive Monocrotophos (MCP) application in agricultural soils has led to its ubiquitous accumulation in the environment. Human health can be adversely affected by chronic exposure to produce and water from such areas, causing endocrine dysfunction, birth defects, blood and nervous disorders. This study investigated the possibility of detecting Monocrotophos-degrading bacteria in soil samples taken from a cotton cultivation field in a local area. We isolated a consortium that could tolerate and neutralize Monocrotophos upto a concentration of 2000 ppm. The consortium on 16S rRNA sequencing were identified as Micrococcus luteus SBR2, Rhodococcus SBR5, Bacillus aryabhattai SBR8, Ochrobactrum intermedium SBK2. Significant tolerance of individual strains in the range of 500-5000 ppm was observed when incubating them in vitro with Monocrotophos in minimal salt medium. An analysis of the degrading genes opdA, mpd, and opd revealed plasmid borne opdA and mpd in the O.intermedium strain and B.aryabhattai strain. All the strains indicated genomic opdA and mpd whereas opd was not detected in plasmid or genomic DNA. The HPLC showed no peak at 2.5min, when individual strains were incubated with Monocrotophos. The HPLC analysis of soil samples incubated with the consortium for two weeks showed complete degradation of Monocrotophos. GC-MS analysis confirmed that Monocrotophos and its solvent cyclohexamide were degraded into non-toxic compounds such as cyclotrisiloxane compounds, acetic acid, and others. This study indicates that the expression of organophosphate hydrolyzing enzymes in the consortium can greatly contribute to the neutralization of organophosphorus compounds and also serve as a bioremediation method for agricultural soils.

Indigo carmine biodegradation by endophytic Microbacterium zeae K5: Enzymatic insights, degradation mechanism, and ecotoxicity analysis

The enormous amount of colored effluent release from dying industries into fresh and marine reservoirs, causing ecotoxicity and serious health problems. Pertaining to this, the current research emphasis on the decolorization and degradation treatment of Indigo carmine (IC). The decolorization of IC with endophytic Microbacteium zeae K5, isolated from the root of the Salix purpurea plant was studied. In a minimal salt medium with shaking, full dye decolorization (400 mg/L) was achieved within a 24 h incubation period. During dye degradation, the activities of enzymes such as laccase (12.02 U/g), manganese peroxidase (4.23 U/g), and quinone dehydrogenase (0.09 U/g) were also observed. The biodegradation of IC into isatin sulfonic acid and isatin was confirmed by UV–VIS spectrophotometry and GC-MS analysis of dye samples extracted with ethyl acetate. Finally, phytotoxicity studies revealed that the IC degraded metabolites toxicity was lower than that of the parent dye compound. The current study demonstrated isolate M. zeae K5 has ability to efficiently break down IC, indicating its potential for future bioremediation uses.

Product development with Cissus quadrangularis (HADJOD) to create awareness among young adults

Indigenous plants thrive in natural ecosystems and have been used for food and medicine in many communities for centuries. Cissus quadrangularis is an indigenous plant with increasing popularity and great potential for nutritional enhancement to improve the functionality of food products and assist with food insecurity in South Africa. The aim of this study was to develop a sensory-acceptable food product using C. quadrangularis and to create awareness and increase acceptability of the plant among young adults. Two quantities of C. quadrangularis were used to make a trendy energy bite with two different quantities of C. quadrangularis 4 g (Sample 1) and 6 g (Sample 2) respectively. The developed food items were tested for sensory, microbiological, nutritional, and shelf-life. An awareness video with C. quadrangularis recipes and information was developed. The nutritional analysis showed the energy bite has minimal fat and salt. Sensory ratings did not vary between samples 1 and 2. A significant number of participants preferred or greatly appreciated the video and expressed interest in preparing foods using C. quadrangularis. A trendy and tasty food product using C. quadrangularis and an information tool may help young people consume an unfamiliar indigenous plant.

Isolation and Molecular Characterization of Polyester-Degrading Bacterial Strains from Municipal Wastewater and Their Application in Microplastic Degradation in Contaminated Wastewater

Diverse synthetic polymers find their regular application in routine life and are disposed of directly into the environment through various sources. The released microplastic and microfibres from the sources creates contamination in both aquatic and terrestrial environments. When these micropollutants enter the food chain, they have adverse effects on the environment and human health. This study focuses on the application of native bacterial strains isolated for the effective degradation of polyester microfibers. The isolated bacterial strains, namely MFB 6, MFB 8, and MFB 11, tolerant to polyethylene glycol (PEG), were identified as Bacillus sp., Paenibacillus sp., and Aeromonas veronii, respectively, with NCBI gene bank accession numbers ON318306, ON318390, and PP237260. Polyester biodegradation efficiency of 10.5%, 12.6% and 8.4% was achieved by MFB 6, MFB 8 and MFB 11, respectively, after 42 days of investigation in minimal salt medium under shake flask condition. In future the application of these microorganisms will help in sustainable management of synthetic microfiber pollutants and find their suitable application in micro plastic degradation in contaminated wastewater.

Screening of Different Fungi Strains Gongronella sp. WICC F60 and Cordyceps sp. WICC F61 for Degradation of Low-Density Polyethylene

Over the past decade, polyethylene (PE) products have become increasingly important in several industries. Their biggest concerns are plastic material degradation resistance and environmental longevity. Therefore, this study aims to find fungi that are capable of degrading low-density polyethylene (LDPE) efficiently. This study uses Gongronella sp. WICC F60, and Cordyceps sp., WICC F61. The fungi were grown on potato dextrose agar for 30 days. Following that, fungal colonies were placed in potato dextrose broth for incubation. The LDPE sample was then cultured with the fungal strain in a minimum salt medium with a 10% inoculum. After 30 days of biodegradation testing, the analysis was done. These studies measured LDPE sample weight loss, pH, and fungal biomass. It was observed that the LDPE sample weight loss increased with time until the end of inclubation. Gongronella sp. WICC F60 and Cordyceps sp. WICC F61 were able to degrade LDPE plastic. Both fungi show an increase in LDPE weight loss. However, Cordyceps sp. WICC F61 shows more efficiency in LDPE degradation compared to Gongronella sp. WICC F60. The LDPE weight loss using Gongronella sp. WICC F60 was 1.07%, which is lower than Gongronella sp. WICC F60's LDPE weight reduction of 5.56%.

Evaluating lignin degradation under limited oxygen conditions by bacterial isolates from forest soil

Lignin, a heterogeneous aromatic polymer present in plant biomass, is intertwined with cellulose and hemicellulose fibrils, posing challenges to its effective utilization due to its phenolic nature and recalcitrance to degradation. In this study, three lignin utilizing bacteria, Klebsiella sp. LEA1, Pseudomonas sp. LEA2, and Burkholderia sp. LEA3, were isolated from deciduous forest soil samples in Nan province, Thailand. These isolates were capable of growing on alkali lignin and various lignin-associated monomers at 40 °C under microaerobic conditions. The presence of Cu2+ significantly enhanced guaiacol oxidation in Klebsiella sp. LEA1 and Pseudomonas sp. LEA2. Lignin-related monomers and intermediates such as 2,6-dimethoxyphenol, 4-vinyl guaiacol, 4-hydroxybenzoic acid, benzoic acid, catechol, and succinic acid were detected mostly during the late stage of incubation of Klebsiella sp. LEA1 and Pseudomonas sp. LEA2 in lignin minimal salt media via GC–MS analysis. The intermediates identified from Klebsiella sp. LEA1 degradation suggested that conversion and utilization occurred through the β-ketoadipate (ortho-cleavage) pathway under limited oxygen conditions. The ability of these bacteria to thrive on alkaline lignin and produce various lignin-related intermediates under limited oxygen conditions suggests their potential utility in oxygen-limited processes and the production of renewable chemicals from plant biomass.

Improvement in Salt Tolerance Ability of Pseudomonas putida KT2440.

Pseudomonas putida KT2440 is a popular platform for bioremediation due to its robust tolerance to environmental stress and strong biodegradation capacity. Limited research on the salt tolerance of P. putida KT2440 has hindered its application. In this study, the strain KT2440 was tested to tolerate a maximum of 4% w/v NaCl cultured with minimal salts medium. Transcriptomic data in a high-salinity environment showed significant expression changes in genes in membrane components, redox processes, chemotaxis, and cellular catabolic processes. betB-encoding betaine-aldehyde dehydrogenase was identified from the transcriptome data to overexpress and enhance growth profile of the strain KT2440 in minimal salts medium containing 4% w/v NaCl. Meanwhile, screening for exogenous salt-tolerant genes revealed that the Na+/H+ antiporter EcnhaA from Escherichia coli significantly increased the growth of the strain KT2440 in 4% w/v NaCl. Then, co-expression of EcnhaA and betB (KT2440-EcnhaA-betB) increased the maximum salt tolerance of strain KT2440 to 5% w/v NaCl. Further addition of betaine and proline improved the salt tolerance of the engineered strain to 6% w/v NaCl. Finally, the engineered strain KT2440-EcnhaA-betB was able to degrade 56.70% of benzoic acid and 95.64% of protocatechuic acid in minimal salt medium containing 4% w/v NaCl in 48 h, while no biodegradation was observed in the normal strain KT2440 in the same conditions. However, the strain KT2440-EcnhaA-betB failed to degrade catechol in minimal salt medium containing 3% w/v NaCl. This study illustrated the improvement in the salt tolerance performance of Pseudomonas putida KT2440 and the feasibility of engineered strain KT2440 as a potential salt-tolerant bioremediation platform.

Biosynthesis of bioplastic polyhydroxybutyrate (PHB) from microbes isolated from paddy/sugarcane fields and fabrication of biodegradable thin film

Polyhydroxybutyrate (PHB) is a polyhydroxyalkanoate (PHA) family microbial polyester. Three Gram-negative bacteria that produce PHB, Acinetobacter baumannii, Enterobacter hormaechei, and Pseudomonas xanthomarina were isolated and cultured in nitrogen-limited minimal salt media. The pH and culture media were further optimized with various glucose and peptone as carbon and nitrogen sources to improve PHB production. FTIR, UV–vis, NMR, TGA, and XRD were used to characterize the PHB produced. The optimal pH for PHB production by Acinetobacter baumannii, Enterobacter hormaechei, and Pseudomonas xanthomarina was discovered to be 6.5, 7.5, and 7.5, respectively. P. xanthomarina produced the highest PHB (7.5 gm/L) in the optimized culture media. Furthermore, PHB-starch thin films were prepared and characterized by XRD before their biodegradability was investigated. The degradation study reveals that 25% of PHB-starch blended thin film has been degraded within 30 days.

Brilliant green decolorization by dye decolorizing peroxidase producing bacterium, Achromobacter insolitus isolated from Forest soils of Similipal Biosphere Reserve, Odisha

Dye-decolorizing peroxidases (DyPs) are recently identified superfamily of heme-containing peroxidases which has received much attention for its potential application in dye decolourization. In the current research, six bacterial colonies (SDB1-6) showing lignolytic activity were isolated from forest soils of SBR using a minimal salt medium supplemented with alkali lignin and screened for DyP activity using brilliant green dye supplemented luria bertani agar medium. The highest DyP activity showing bacterium was identified using biochemical and 16SrRNA sequencing and was identified as Achromobacter insolitus. A. insolitus was found to be an efficient strain showing the highest DyP activity of 2.7 U/mL/ml at un-optimized condition. The RSM optimization was conducted to increase the DyP enzyme activity. A. insolitus demonstrated DyP activity of 6.20 U/mL/min with an increase of 2.29 times of enzyme activity in optimal condition of pH 7.0, temperature 25 °C, H2O2 concentration 0.1 mM, and time 24 h. The bacterium was further screened for dye decolorization taking crystal violet, methyl orange, methylene blue, brilliant green and methyl red dyes supplemented in LB medium. The bacterium showed maximum brilliant green degradation ability was analyzed using UV-Vis and FTIR analyses to characterize the degraded product. The highest brilliant green degradation activity of the A. insolitus in the present study could be exploited for bioremediation of brilliant green contaminated industrial effluents in a ecofriendly and cost effective way.

Degradation of Dimethyl Phthalate and Diethyl Phthalate by Bacteria Isolated from Jazan, Saudi Arabia

P hthalate esters (PAEs) are commonly utilized in commercial, industrial, and medical applications. Various concentrations of PAEs have been detected in seawater samples and treated wastewater obtained from wastewater treatment plants in Saudi Arabia. Since these compounds pose adverse effects to human health, it is vital to develop efficient strategies to eliminate phthalate contamination from environments. In the present study, an enrichment technique was used to isolate phthalate-degrading bacteria from seawater and from activated sludge collected at Jazan Wastewater Treatment Plant, Saudi Arabia. Bacteria with the capability of degrading dimethyl phthalate (DMP) or diethyl phthalate (DEP) were isolated using minimum salt medium supplemented with these compounds as the sole carbon and energy source. High-performance liquid chromatography (HPLC) was utilized to evaluate the residual concentration of DMP and DEP. Using the 16S rRNA gene sequencing technique, the isolates with maximum DMP biodegradation activity were identified as Achromobacter sp. M1 and Pseudomonas sp. M2, while the isolates with maximum DEP biodegradation activity were identified as Pseudomonas sp. E2 and Pseudomonas sp. E3. The optimum bacterial growth was achieved at 30°C, pH 7.0, and 2% NaCl, except for Pseudomonas sp. E3, which demonstrated its maximum growth in the absence of NaCl. The highest biodegradation rate for all the bacterial strains (> 99.0%) was achieved at 30°C, pH 7.0, and up to 2% NaCl within 4 days. Concurrently, Pseudomonas sp. M2 and Pseudomonas sp. E2 exhibited remarkable degradation rates (97.5% and 56.7%, respectively) at 4% NaCl whereas Pseudomonas sp. E3 showed its highest DEP degradation (82.4%) after 4 days in the absence of NaCl. This study offers potential candidates, including Achromobacter sp. M1, Pseudomonas sp. M2, Pseudomonas sp. E2, and Pseudomonas sp. E3, for the proficient biodegradation of DMP and DEP.

Exploring the potential of bacterial consortium for the treatment of paper mill effluent treatment through various treatment strategies and evaluation of their toxicity

Paper mill effluent containing kraft lignin (KL) and other toxic compounds poses serious environmental health concerns due to its potential for bioaccumulation. A prospective bacterial consortium is still needed for the remediation of paper mill effluent. Therefore, the current work aims to explore the potential of consortium, i.e. Bacillus cereus, B. paramycoides, and B. aryabhattai via different treatment strategies: batch, continuous, multipulse, and dissolved oxygen (DO) stat fed-batch for maximum detoxification of effluent under optimised conditions. A minimal salt medium containing 1.0 % glucose, 0.5 % ammonium nitrate, and pH 8.0 was the optimum condition for the consortium to degrade 1000 mg/L of kraft lignin in the effluent. Laboratory adaptation evolution (LAE) studies showed that the maximum number of bacterial generations was observed within 178 h at 5th cycle for 3000 mg/L kraft lignin. The maximum removal of KL, color, chemical oxygen demand (COD), biological oxygen demand (BOD), and total phenol by the dissolved oxygen stat fed-batch treatment strategy was 94 %, 86 %, 91 %, 90 %, and 97 %, respectively. Phytotoxicity testing of the consortium-treated effluent on Vigna radiata L., and Trigonella foenum-graecum L. revealed a reduction in phytotoxicity by ∼66 % and ∼68 %, respectively. The genotoxicity study on Allium cepa L. showed that the percent of aberrant cells with different chromosomal aberrations was decreased in consortium-treated effluent as compared to untreated effluent. This work provides a new insight and strategy for the paper mill effluent treatment at an industrial scale. Statement of environmental implicationThe paper mill effluent contains various hazardous compounds; chlorinated phenols, dioxins, kraft lignin, and endocrine disrupting compounds, when discharge from industries without proper treatment. This effluent causes mutagenic, clastogenic, carcinogenic, and endocrine-disrupting mechanisms in flora and fauna. This study provides a comparative performance evaluation of different treatment strategies: batch, continuous fed-batch, multipulse fed-batch, and dissolved oxygen stat fed-batch, for paper mill effluent treatment using a bacterial consortium for maximum removal of kraft lignin, color, chemical oxygen demand, total phenol concentration, and quantified ligninolytic enzyme production. Treated effluent showed a lesser phytotoxic and genotoxic effect. Therefore, the results of this study are suitable for environmental restoration. Significance of studyContrastingly, throughout this study, found that bacterial consortium have superior detoxifying qualities of paper mill effluent compared to pure cultures, via different treatment strategies: batch, continuous, multipulse, and dissolved oxygen stat fed-batch strategies under optimised conditions at lab scale. According to these results, such dissolved oxygen stat fed-batch strategy mediated treated effluent that promotes seed germination and showed a higher mitotic index of root cells of the plant in contrast to untreated effluent. Therefore, these treatment strategies are adequate, effective, and sustainable to reduce the significant pollution load in effluent.