Potential Of Bacterial Isolates Research Articles

Plant growth promotion activities of Bacillus spp. isolated from Jakrem hot water spring of Meghalaya, North East India

The study aims to investigate plant growth promotion (PGP) activities of thermophilic bacteria isolated from the Jakrem hot spring in Meghalaya, North-East India, and determine their effect on Brassica juncea's growth. The bacteria were isolated by a culture-dependent approach following a serial dilution method in a nutrient agar medium. All the isolates were determined for PGP attributes such as indole acetic acid, phosphate solubilization, hydrolytic enzymes, and siderophore production. The potent bacterial isolates were characterized by 16S rDNA sequencing and phylogenetic analysis. Altogether, 53 bacterial isolates were obtained, most belonging to the genus Bacillus. Of the total isolates, 37.7% exhibited both PGP and hydrolytic enzyme activities. Three isolates, namely JAB1, JAB8, and JAB100, showed promising PGP and were identified as Bacillus velezensis, B. proteolyticus, and Bacillus sp., respectively. The PGP attributes of these isolates were determined in vivo on B. juncea, and their effects were measured in terms of shoot and root length biomass and biochemical contents. It was observed that combined inoculation of all three isolates significantly enhanced the growth and development of B. juncea, evident by increased shoot and root length, fresh and dry weight, and higher levels of protein, phenol, flavonoid, and chlorophyll content compared to the control. In conclusion, the study highlights the potential application of thermophilic Bacillus spp. from hot springs as bioinoculants to enhance crop productivity in sustainable agricultural practices.

Screening for drought-tolerant mungbean root nodule bacteria with multiple plant growth promoting traits in Aridisol

Mungbean (Vigna radiata L. Wilczek) is an economically important legume crop grown across India. The growth and yield of the crop have been declining over the recent years due to climate change which leads to decrease in soil moisture. Applications of drought-tolerant plant growth-promoting (PGP) rhizobial strains have been found to enhance crop productivity under water deficiency. Therefore, the objective of this study was to screen the bacterial strains from the mungbean root nodule that may help in improving the plant growth under drought condition. Bacteria were isolated from mungbean root nodules and screened for in vitro drought-tolerance using different concentrations of PEG 6000 at 10, 20, 30 and 40 %, and temperature-tolerance at 30, 35, 40 and 45 °C. In primary screening, out of 98 root nodule bacterial isolates tested, only 25 % showed drought-tolerance at 40 % polyethylene glycol (PEG)-6000 while 22 % of bacteria survived at 45 °C. During secondary screening on combined stress-tolerance, only 8 % of isolates showed tolerance of 40 % PEG-6000 at 45 °C. The in vitro drought-tolerance of bacteria varied significantly according to their sampling region/district. Various PGP traits, i.e., nitrogen fixation, phosphate solubilization, and production of indole acetic acid, ammonia, and 1-aminocyclopropane-1-carboxylate (ACC) deaminase, were analyzed in isolated stress-tolerant bacteria, which may contribute towards stress-tolerance and crop productivity in mungbean. The most promising drought-tolerant nodule bacterial isolates were identified as Rhizobium sp. and Pseudomonas indica, respectively by 16S rRNA sequencing. Moreover, bacterial isolates MuJs52b, MuJs53b, MuJs72a and MuBk32b, which exhibited drought-tolerance of 40 % PEG-6000 and different PGP activities, were used as bioinoculant on mungbean plants grown under moderate to severe drought at 50 and 25 % of field capacity (FC) in pot experiment. Bacteria inoculated plants showed maximum increase in nodule dry weight (56.5 %) and shoot dry weight (87.5 %) per plant even under severe drought at 25 % FC. The results indicated that application of four potential nodule bacterial isolates, which were able to tolerate drought stress of 40 % PEG-6000, and having multiple PGP traits, showed stimulation of the mungbean growth even up to 25 % FC. These plant growth-promoting nodule bacterial strains may be used for the enhancement of mungbean crop productivity under drought stress and could be used as biofertilizer.

Optimization of Growth Response Parameters, Screening and Molecular Detection of Pesticide Degradation Genes in Bacterial Isolates from Agricultural Soils

Study’s Novelty/ Excerpt This study demonstrated the capability of bacteria isolated from farmland soils in Kano Metropolis to biodegrade dichlorvos and carbofuran pesticides, identifying Bacillus sp., Serratia sp., and Pseudomonas sp. as key degraders. Optimization experiments revealed that Serratia sp. thrived at 100 mg/L dichlorvos concentration and 35°C, while Pseudomonas sp. showed maximum growth at 300 mg/L carbofuran concentration and 30°C, both with a pH of 7.0, 100 rpm agitation, and 5-day incubation period. Molecular analysis confirmed the presence of opd and mcd genes in Serratia sp. and Pseudomonas sp., respectively, highlighting their potential for effective bioremediation of pesticide-contaminated soils. Full Abstract Pesticides are organic compounds synthesized and used for pest control. The excessive and continuous dispersion of pesticides in the environment results in environmental pollution, necessitating remediation. This study investigated the potential of bacteria isolated from farmland soils in Kano Metropolis, Kano State, Nigeria, with a history of dichlorvos (2,2-dichlorovinyldimethylphosphate) and carbofuran (2,3-dihydro-2,2-dimethyl-7-benzofuranyl methylcarbamate) application, to biodegrade these pesticides. Three sampling sites were involved in sample collection, and the soil physicochemical parameters from each sample were determined. Isolation, identification, and screening of the bacterial isolates capable of utilizing the pesticides as sole sources of carbon were carried out. The following parameters (concentration of the pesticides, pH, temperature, agitation, and incubation time) were optimized to maximize degradation. The potent bacterial isolates were further subjected to molecular analysis for the detection of opd and mcd genes. The pesticide-degrading bacteria were identified as Bacillus sp., Serratia sp., and Pseudomonas sp. Serratia sp. recorded the highest growth in the presence of 1% v/v dichlorvos, while Pseudomonas sp. exhibited maximum growth at a 1% w/v carbofuran concentration. The optimized conditions that yielded the maximum microbial growth are: 100 mg/L pesticide concentration for Serratia sp and 300 mg/L for Pseudomonas sp, a pH of 7.0 and an agitation level of 100 rpm for both organisms, a temperature of 35°C for Serratia sp and 30°C for Pseudomonas sp, and an incubation time of 5 days for both organisms. The opd and mcd genes were identified from Serratia sp. and Pseudomonas sp. respectively. These results suggest that the isolated bacteria have the potential to degrade dichlorvos and carbofuran pesticides from the contaminated soil

Biological control potential of worrisome wheat blast disease by the seed endophytic bacilli.

Crop production often faces challenges from plant diseases, and biological control emerges as an effective, environmentally friendly, cost-effective, and sustainable alternative to chemical control. Wheat blast disease caused by fungal pathogen Magnaporthe oryzae Triticum (MoT), is a potential catastrophic threat to global food security. This study aimed to identify potential bacterial isolates from rice and wheat seeds with inhibitory effects against MoT. In dual culture and seedling assays, three bacterial isolates (BTS-3, BTS-4, and BTLK6A) demonstrated effective suppression of MoT growth and reduced wheat blast severity when artificially inoculated at the seedling stage. Genome phylogeny identified these isolates as Bacillus subtilis (BTS-3) and B. velezensis (BTS-4 and BTLK6A). Whole-genome analysis revealed the presence of genes responsible for controlling MoT through antimicrobial defense, antioxidant defense, cell wall degradation, and induced systemic resistance (ISR). Taken together, our results suggest that the suppression of wheat blast disease by seed endophytic B. subtilis (BTS-3) and B. velezensis (BTS-4 and BTLK6A) is liked with antibiosis and induced systemic resistance to wheat plants. A further field validation is needed before recommending these endophytic bacteria for biological control of wheat blast.

Qualitative and Quantitative Analysis of Sodium Dodecyl Sulphate (SDS) Degradation by Pseudomonas Species

Sodium dodecyl sulphate (SDS), an anionic surfactant widely used in cleaning and cosmetic products, poses significant environmental risks when untreated effluents are discharged into terrestrial and aquatic ecosystems. In this study, a potential bacterial isolate identified as Pseudomonas sp. FD-2aii, which could grow in the presence of SDS, was successfully isolated from industrial wastewater. Bacteria were used in the SDS degradation study based on their ability to utilise SDS as the sole carbon source. Isolate FD-2aii showed growth after incubating at 30 °C with shaking at 150 rpm for 24 h. The residual SDS concentration and percentage of SDS degradation in the bacterial cultures were quantified using a methylene blue active substances (MBAS) assay. This study focused on the reduction in SDS concentration over a ten-day period and provided a clear indicator of the degradation efficacy of isolate FD-2aii.

Grasshopper (Oxya chinensis) Gut Bacteria and their Cellulolytic Activity

Lignocellulose is a core component of plant biomass and the most abundant carbohydrate polymer in nature. It is cheap and renewable and has several potential applications; however, it remains underutilized because of its recalcitrance to degradation. Cellulolytic microbes have been found in the gut of herbivorous insects, such as grasshoppers. This study aimed to isolate lignocellulolytic bacteria from the gut of grasshoppers (Oxya chinensis) and determine their diversity and potential biomass-degrading activity. A total of 27 culturable isolates were obtained from the grasshopper foregut, midgut, and hindgut. The bacteria hydrolyzed cellulose and lignin, as indicated by a cellulolytic index of 0.12–1.23 and ligninolytic index of 0.1–1.47. Five potential cellulolytic bacterial isolates were selected. Based on 16S rRNA sequencing, the isolates were identified as Bacillus wiedmannii (foregut), Bacillus marcorestinctum, Bacillus halotolerans (midgut), Paenibacillus zanthoxyli, and Bacillus hominis (hindgut). The highest specific cellulolytic activity (0.0068 U/mg) was detected in B. wiedmannii (OCF2), which could be exploited as a potential source of cellulases.

Surfactin production from Bacillus cereus AHMNAZ1 and its potential applications

BACKGROUND: Biosurfactants are surfactants derived from several types of microorganisms such as bacteria, yeasts and fungi as membrane components or secondary metabolites. OBJECTIVE: To increase BS productivity as a biocompatible, low-toxic substitute for chemical surfactants employed in modern industry and the huge variety of applications they are used in. METHODS: Different media were used in isolation of the biosurfactant BS producers. The most potent bacterial isolate was analysed by 16S-rRNA. Plackett Burman and Box-Behnken Designs were used for optimization conditions. BS was purified by and characterized. RESULTS: Only one strain demonstrated great BS productivity, excellent emulsifying capability (54.5±0.1%) and oil spreading activity which analysed as Bacillus cereus AHMNAZ1 with accession number OP714421.1. The BS was lipopeptide in nature, identified as a surfactin which was stable and has Critical Micelle Concentration of 60 mg/L. Isolated surfactin showed excellent activity against Colon Carcinoma and Breast Carcinoma cell lines and can be used as antimicrobial agent. CONCLUSION: The study found a cheaper way of creating biosurfactants from agro-industrial wastes, delivering a twofold benefit of lowering environmental pollution and manufacturing useful biotechnological products (biosurfactants) with high activity and thermostability. Moreover, it can be used for the bioremediation of oil-polluted soils and in medical fields.

Comparison of Bacterial Diversity in Water Samples of Aquaculture, Aquaponic and Hydroponic System

Aquaponics is the production of aquatic organisms using less water while hydroponic is the production of vegetables and plants without soil. Microbial diversity in these culture systems includes bacteria, protists, fungi, and archaea. Among microbes, bacteria are a pivotal and crucial aspect of aquaponic, aquaculture, and hydroponic system, acts as the bridge connecting the waste of fish to the fertilizer for plants. Current research aims to compare the bacterial diversity in water samples of aquaculture, aquaponics, and hydroponic systems. For this purpose, water samples were taken from aquaculture, aquaponic, and hydroponic system. Aliquots of the samples were used for the isolation of bacterial species based on standard procedures. Colonies were purified after isolation by membrane filtration by twice subculturing using the method of streaking plate. Potential bacterial isolates were characterized and identified up to the specie level by following standard microbiological techniques. Different bacterial species were isolated from water samples during the study include Aeromonas spp., Bacillus spp., Nitrosomnas spp., Nitrobacter spp., Psuedomonas spp., Acinetobacter spp., Enterobacter spp., Streptomyces spp., Escherichia coli and Staphylococcus spp. Bacillus spp. present in all these systems. Nitrosomnas spp. and Psuedomonas spp., show similarity in an aquaponic and hydroponic system. Enterobacter spp., Streptomyces spp., shows similarity in aquaculture and hydroponic system. It is observed that the water was full of beneficial and pathogenic bacteria which exhibited potential impact on the cultured fish and plant species.

Plant growth promotion of radish by rhizosphere dwelling bacteria

The present study was carried out with the aim to develop a plant growth-promoting rhizobacterial inoculant for improving the growth of radish. A total of 20 rhizobacteria were isolated and then tested for multifarious plant growth-promoting traits. The isolates exhibited tricalcium phosphate and zinc solubilization, production of siderophores, auxins, ammonia and growth on different nitrogen free medium. Out of 20 isolates, two potential bacterial isolates (RM3 and RL3) were selected on the basis of PGP traits for evaluation of their potential to promote growth of radish under pot conditions. In green house experiment, these isolates when used as consortium showed a significant improvement in soil enzymatic activities (viz. dehydrogenase: 12.99 µg TPF formed h-1 g of soil-1, alkaline phosphatase: 11.94 µg PNP formed h-1 g of soil-1 and urease: 401.65 µg urea hydrolyzed formed h-1g of soil-1) and plant growth parameters (shoot length: 38.76 cm, leaf area: 267cm2, fresh leaf weight:106.05 g, dry leaf weight:1.23 g, number of leaves per plant: 23, fresh root weight:111.69 g, dry root weight: 2.06 g, root length: 34.04 cm and root diameter: 3.33 cm) relative to control as well as other bioinoculants. These bacteria were tentatively identified as Bacillus (RM3) and Pseudomonas (RL3) on the basis of biochemical tests.

Identification of Potential Biofertilizer and Bioremediator Bacteria from Upland Soil Based on 16s rDNA Sequence Analysis

The long-term presence of synthetic pesticides on agricultural land can lead to a decline in soil fertility. Synthetic pesticides inhibit the activity of essential enzymes in the soil and suppress beneficial microbial populations for plants. One potential approach to mitigate the extent of contamination caused by synthetic pesticides involves the utilization of indigenous pesticide-resistant bacteria. Several upland soil bacteria from Banyumas Regency, Central Java Province, Indonesia, were successfully isolated from a previous study. The isolated bacteria have the potential to be developed as pesticide bio-remediators and biofertilizers. The bacterial isolates are expected to have characters that support plant growth through their ability to provide dissolved phosphate. However, the potential bacterial isolates need to be identified by molecular approaches. This study was conducted to identify bacterial isolates of GT2, SR1, SW1, and PA1 by 16S rDNA sequencing analysis. The results showed that isolate GT2 was placed within a group of reference strains of Bacillus proteolyticus, isolate SR1 was placed within a group of B. paramycoides, isolate SW1 was set within a group of B. albus, and isolate PA1 was placed within a group of Acidovorax delafieldii. The genetic distance of isolate GT2 and B. B. proteolyticus, isolate SR1 and B. paramycoides, isolate SW1 and B. albus were 0.0000 each, and isolate PA1 and A. delafieldii were 0.0061.

Toxicity assessment of heavy metal (Pb) and its bioremediation by potential bacterial isolates.

Lead (Pb) is a non-essential metal with high toxicity, is persistent, is not biodegradable, and has no known biological function. It is responsible for severe health and environmental issues that need appropriate remediation. Therefore, microbes have thrived in a lead-contaminated environment without exhibiting any negative impacts. The present study aimed to examine the toxic effects of lead on animals and the isolation, identification, and characterization of lead-resistant bacterial strains and their biodegradation potential. After oral administration of lead for 4weeks, mice showed an elevated level of leukocytes and a decrease in TEC, Hb, PCV, MCV, MCH, and MCHC levels. However, a decline in body weight and inflammation and oxidative stress was observed in liver tissues. To remediate toxic heavy metal, lead-resistant bacterial strains were isolated, among which Enterobacter exhibited maximum degradation potential at high lead concentrations. It was identified by molecular basis and after 16S rRNA sequencing, and 99% resemblance was observed with Enterobacter cloacae. FT-IR analysis of the bacteria illustrated the presence of functional groups, including hydroxyl, carboxyl group, sulfide, and amino groups, on the bacterial cell surface involved in the adsorption of lead. Moreover, electron microscopy (SEM) revealed the morphological and physiochemical changes in the bacterial cell after biosorption, indicating the interaction of Cu ions with functional groups. To summarize, the findings show the highly toxic effects of lead on animals and humans and its effective biodegradation by the bacterial strains in the lead-contaminated environment. This biological strategy can be an ideal alternative to remediate heavy metals from contaminated sites to clean up the environment.

Isolation and Molecular Identification of Cellulase producing bacteria from soil and litter in Veerakkal forest area, The Western Ghats, India

The cellulolytic bacterial strains were screened from both soil and litter samples in different study sites of Veerakkal forest, Manar beat, The Western Ghats, India. In the current investigation, out of 64 and 48 differentiated total purified isolates, 53 soil isolates and 34 litter isolates were screened based on the CMC method. The percent wise calculation indicated that 82 % were cellulase positive while 18 % were negative in soil isolates. Likewise, 70 % of them were positive while 30 % were negative cellulase strains in litter isolates. The average hydrolysis capacity (HC) values ranged between 1.67 to 3.25 cm. The highly potential cellulolytic bacterial isolates viz. Bacillus thuringiensis, Bacillus licheniformis, Bacillus cereus, Bacillus sporothermodurans, Bacillus circulans, Bacillus albus, Bacillus amyloliquefaciens, Lysinibacillus sphaericus and Bacillus mobilis were identified from soil. Likewise, the litter cellulolytic bacterial species such as Bacillus sp., Lysinibacillus macroides, Bacillus paramycoides, Solibacillus silvestris, Pseudomonas stutzeri, Bacillus toyonensis, Bacillus subtilis, Bacillus pacificus, Bacillus flexus, Bacillus paranthracis and Pseudomonas putida were identified. The cellulolytic bacterial population was higher during the monsoon because of the presence of higher moisture content in leaf litter. However, the cellulolytic bacterial population of soil was higher during the pre-monsoon season because of the continuous breakdown of litter which inhaled more cellulolytic strains in the soil. Finally, it was concluded that corresponding with seasonal changes, the cellulolytic bacterial community also changed and it plays a significant role in the mineralization process.

Decolourization of Textile Dyes with Biotechnological Potent Bacterial Isolates

The discharge of effluents from the textile industries to aqueous bodies is currently one of the biggest concerns of environmentalists. Dyes used in the textiles industries create pollution in the environment. The application of biological treatments is one of the most economically viable systems to decolorized effluents using bacterial isolates (TBSP, TBSP2). In this sense, studies were carried out tests for the removal of colour of Congo red, Methyl orange, Brilliant Blue, using bacterial strain. Firstly, all two bacterial strains were isolated from different environments. Then, tests were performed to verify which concentration of the dye would be limit for the growth of each microorganism. In addition to decolourization tests, other parameters such as pH, biomass, total proteins and toxicity of the metabolites formed were also monitored. The bacterial strain, isolated from the river environment, was able to decolourization concentrations of 100ppm to upto 700ppm respectively for the, Coomasie Brilliant blue, Methyl orange and Congo red. TBSP1 and TBSP2 discoloured respectively at concentrations 100ppm to 700 ppm , while the intercropping (consortium) of the two bacteria discoloured at a concentration of 700ppm for the three dyes tested individually. In these cultivation conditions, the decrease in the quality rate varied with the lowest rate observed in the assay containing Congo Red and Congo red dye and the highest removal rate in the assay containing the intercropping and the CBBR dye. The results shows that the bacteria biotechnological potent bacteria present initial pot in the decolourization of textile dyes, initial pot were shows the ability to decolorize azo dyes.

Optimization of Indole-3-acetic acid production by Bacillus velezensis isolated from Pyrus rhizosphere and its effect on plant growth

Indole-3-acetic acid (IAA) is an important plant growth promoting hormone produced as secondary metabolite by many microorganisms. The current study aims to optimize conditions for IAA production by a rhizobacterial isolate and evaluation of its effect on plant growth. Seven bacterial isolated were purified from the rhizosphere of pear-tree and screened for IAA production and optimum production medium. The most potent bacterial isolate (S5) was selected for further investigations and molecularly identified using (16S rRNA). The selected isolate was identified as Bacillus velezensis strain MOST-IAA and given the accession number (ON792392.1) in National Center for Biotechnology Information (NCBI). For maximum IAA productivity, twenty one nutritional factors were screened for their significance on IAA using Placket Burman design and the significant factors were used for statistical modeling of the production conditions using Box-Behnken design. The produced model and optimization resulted in maximum IAA (56.60 μg/ml) at: 4.41 g/l, D(+) mannose; 8.66 g/l, mannitol; 0.93 g/l, tryptophan; 5.88 g/l, potassium nitrate; 1.29 g/l, ammonium chloride; 28.5 °C, temperature and 7.69, initial pH with correlation of 94.76% to the theoretical results. The produced IAA has been extracted and used in irrigation of barley seed for 10 days. Data showed significant differences among the test and control barley, especially in the length of the produced roots. Bacillus velezensis can be used to increase the soil fertility or biotechnologically used for production of IAA to be applied for plant growth improvement.

Screening of potential bacterial isolates against Phytophthora capsici and its plant growth-promoting effect on pepper plants

Phytophthora blight, is the most devastating disease of pepper production. To increase agricultural yield and control diseases, many countries in the world use synthetic agrochemicals. However, it has negative effects on human health and the environment, but there are few reports on its biological control. Out of sixty bacterial strains, four that showed biocontrol and plant growth promotion, namely Enterobacter hormaechei, Rhizobium sp., Pseudomonas fluorescens, and undetermined (AAULE51), which were isolated and identified using biochemical tests and 16S RNA sequences. All bacterial strains that showed greater than 55.5% growth inhibition of Phytophthora capsici in dual culture were selected for greenhouse and field studies. Also, the antimicrobial activity of the cell-free filtrate of the strains were assessed. AAULE51 was found to be the best inhibitor against P. capsici, ranging from 90.34 to 100% at a concentration of 20%–75%. The effects of bacterial strains on seed germination, vigor index, seedling height, and fresh weight of pepper plants were measured in vitro and showed 70−90.6%, 1069.6−2650%, 37−48 mm, and 64−70 mg, respectively. In greenhouse and field studies the biocontrol efficacy of antagonistic bacteria against P.capsici ranged from 0.6% to 94.2%, and 11%–84.6% respectively. The maximum reduction in disease severity was shown when treated with AAULE41+ AAULE51 (61.1%–94.2%). Therefore, these results suggest that selected potential bacterial strains are good candidates for agricultural biofertilizers and biopesticides.

Isolation of Furfuryl Alcohol Degrading Bacteria from Aromatic Compound‐Based Industrial Waste

AbstractPolyfurfuryl alcohol (PFA) is one of the thermoset biopolymers that can meet the demand of green polymers. Furfuryl alcohol (FA) is the building unit of this promising biopolymer. This work is a preliminary study of microbial degradation of FA. FA degrading bacterial strains have been isolated from sites exposed to various aromatic compounds such as industrial effluents. A total of eight bacterial isolates have been selected as potential FA degraders based on their growth, with FA as the sole carbon source, colony morphology, and biochemical characteristics. In addition, the biokinetic study of the potent bacterial isolates has been performed, and a specific growth rate evaluated.

Isolation and screening of low-density polyethylene (LDPE) bags degrading bacteria from Addis Ababa municipal solid waste disposal site “Koshe”

PurposeThis study aims to screen bacterial isolates from the Addis Ababa municipal solid waste dumping site (Koshe) for the biodegradation of low-density polyethylene bags and analyzes their efficiency in degrading plastic bags.MethodsIn this study, low-density polyethylene bag-degrading bacteria were isolated from the Koshe municipal solid waste disposal area in Addis Ababa, Ethiopia. Screening of isolates for low-density polyethylene bag biodegradation was carried out using a clear zone method. Additionally, the efficiency of the isolates for low-density polyethylene biodegradation was evaluated using the weight loss method, scanning electron microscopy analysis, and Fourier transform infrared analysis. Finally, molecular identification of potential low-density polyethylene degrader bacterial isolates was done by 16S rDNA sequencing.ResultsIsolates KS35, KS14, and KS119 resulted in significant weight loss of low-density polyethylene film (42.87 ± 1.91%, 37.2 ± 3.06%, and 23.87 ± 0.11% weight loss, respectively). These isolates were selected for further biodegradation study using scanning electron microscopy and Fourier transform infrared analysis. Scanning electron microscopy analysis shows the formation of pores, pits, and distortion of the plastic surface. Fourier transform infrared analysis indicates the appearance of new peaks at the surface of low-density polyethylene films. Phylogenetic analysis of the three potential bacterial isolates was also carried out, and the result indicates that the sequence of isolate KS35 had 99% similarity with sequences of Methylobacterium radiotolerans MN525302. Isolate KS119 had 100% similarity with Methylobacterium fujisawaense KT720189, and the sequence of isolate KS14 had 99% similarity with species of Lysinibacillus fusiformis.ConclusionsWeight loss, scanning electron microscopy analysis, and Fourier transform infrared analysis results show that isolates KS35, KS14, and KS119 have high potential in degrading low-density polyethylene bags.

Bacterial Profile and Their Antimicrobial Susceptibility Pattern of Isolates Recovered from Intensive Care Unit Environments at Wachemo University Nigist Ellen Mohammed Memorial Comprehensive Specialized Hospital, Southern Ethiopia.

Bacterial contamination of indoor hospitals, especially in intensive care units is a serious health hazard in the world with a high morbidity and mortality rates. Particularly, multidrug-resistant bacteria can cross-contaminate medical devices, inanimate surfaces, health care providers, and patients in the intensive care unit. This study was aimed to assess the bacterial profile and their antimicrobial susceptibility patterns of bacterial isolates from intensive care unit at WUNEMMCSH (Wachemo University Nigest Ellen Mohammed Memorial Compressive Specialized Hospital), Southern Ethiopia. A hospital-based cross sectional study was conducted on 180 intensive care unit environmental samples at WUNEMMCSH from August 1, 2022, to October 30, 2022. In this study, a total of 180 swab samples were collected from medical devices, inanimate surfaces, patients, and health care providers from the intensive care unit by using sterile cotton-tipped swabs moistened with normal saline. Then, bacterial isolates were identified using the standard culture method, Gram stain, and biochemical tests. Antimicrobial susceptibility tests for bacterial isolates were performed by using the Kirby Bauer disk diffusion method. Data were entered into EpiData Version 4.6 cleanup and exported to SPSS V25 for analysis. A total of 180 swab samples were processed from intensive care unit environments, and 143 (79.4%) were found to have been contaminated by at least one potential pathogenic bacterial isolate. A total of two hundred and thirty-eight bacteria were isolated. Of these, the predominant bacteria were coagulase-negative Staphylococci 72 (30.3%), S. aureus 61 (25.6%), E. coli 41 (17.2%), and K. pneumoniae 30 (12.6%). Seventy (49%) out of all swabbed samples were contaminated with mixed isolates. In the antimicrobial susceptibility tests, 19 (86%) Gram-positive bacteria and 25 (76%) Gram-negative bacterial isolates were susceptible to nitrofurantoin, respectively. Vancomycin was sensitive to 83% of Gram-positive isolates. Gram-positive and Gram-negative isolates from irrespective sources showed multidrug resistance in 56.4% and 76.2%, respectively. The inanimate hospital environments, medical device, health care providers, and patients in ICU rooms of WUNEMMCSH (Wachemo University Nigest Ellen Mohammed Memorial Comprehensive Specialized Hospital) were colonized with 143 (79.4%) of potential pathogenic bacterial isolate, which can cause nosocomial infections with high rates of morbidity and mortality among patients. The frequencies of multidrug-resistant 159 (66.8%) bacterial pathogens were alarmingly high. Therefore, to reduce the risk of bacterial contamination and MDR, strict adherence to hospital infection prevention and control measures should be enforced. These measures include regularly performing hand hygiene, periodic disinfection, and sterilization of medical equipment.

Bacterial Contamination of Neonatal Intensive Care Unit

Background and objectives. The environmental impact assessment plays an important role in ensuring environmental media. This study aimed to assess the environmental pollution of the neonatal intensive care unit in Al-Jala hospital of obstetrics and gynecology, Tripoli, Libya through environmental monitoring of bacteria on different surfaces. Methods. A cross-sectional, descriptive study was carried out in the neonatal intensive care unit from December- to February 2022 at Al-Jala hospital, Tripoli. A total of 61 samples were collected with a sterile swab from high-contact environmental surfaces. Isolation, identification, and antibiotic resistance of bacterial isolated were performed by standard technique. Blood culture isolates from neonatal intensive care unit patients were compared with the environmental isolates during the study period. Results. Out of 61 samples, bacterial growth was observed in 58 samples, out of which 40 (68.9%) were gram-positive and 18 (31.03%) were gram-negative. The observed gram-positive bacterial isolate was Staphylococcus aureus 13(32.5%), and most of gram-positive isolates were recovered from an incubator, suction tip, stethoscope, ambu bag, and staff hand. The potential gram-negative bacterial isolates were E. coli 10 (55.5%), and the majority of gram-negative isolates were recovered from the door handle, suction tip, neonate breathing tube, and staff hand. The isolated bacteria were resistant to amoxicillin (41.3%), clindamycin (39.6%), imipenem, and tetracycline (27.5%). Common potential pathogens isolated from the blood culture of NICU patients were staphylococcus aureus. Conclusion. Bacterial contamination of objects and instruments in neonatal intensive care units was high (95%). This study emphasizes the need for rigorous decontamination protocols and hand hygiene. Clindamycin and tetracycline may be used for empirical therapy in clinically suspected cases of isolates.

Production of poly-(R)-3-hydroxybutyrate from halophilic bacterium Salinivibrio sp. utilizing palm oil mill effluent as a carbon source

The accumulation of plastic waste has become an emerging threat to the ecosystem. Reducing plastic waste can be overcome by replacing petrochemical-based plastics with biodegradable ones, such as poly-(R)-3-hydroxybutyrate (PHB). In the present study, we have successfully isolated, characterized, and optimized the PHB yield produced by halophilic bacteria isolated from salt lake Gili Meno, Lombok, Indonesia, utilizing palm oil mill effluent (POME) as the carbon source. Bacterial screening found that isolated bacteria from the bottom of the lake produced the highest PHB yield, mainly when the bacterial isolate was grown in the medium containing 15% (v/v) POME, 5% (w/v) NaCl, as well as 0.1% (w/v) yeast, and 0.1% (w/v) ammonium sulfate. The highest PHB yield produced by the bacterial isolate in this medium was about 5.0 ± 0.8 mg/L. Ribotyping has identified the bacterial isolate as Salinivibrio sp. with 99.9% similarity to the 16S rRNA gene of Salinivibrio sp. YCSC6 (GenBank accession no. CP039516.1). Scanning electron microscope images of the produced PHB exhibited the morphology of sheet-like structures. Thermal analysis revealed that the produced PHB has maximum decomposition and degradation temperatures at 442.4 °C and 282.9 °C, respectively. Therefore, Salinivibrio sp. is a potential bacterial isolate for producing high-yield PHB with high thermal stability. In addition, this bacterial strain is also a productive bacterium in bio-converting POME into PHB, thereby resolving the environmental issue of liquid waste from palm oil industries.