Bacterium Bacillus Licheniformis Research Articles

Characterization of Crude Oil Degrading Marine Bacterium Bacillus licheniformis

Characterization of Crude Oil Degrading Marine Bacterium Bacillus licheniformis

A convenient synthesis, characterization and biological evaluation of novel schiff base heterocycles as potential antimicrobial, antitubercular agents and their structural activity relationship

A series of (E)-1-methyl-3-((substituted phenylimino)methyl)quinolin-2(1H)-one schiff bases (3a-j) bearing quinoline moiety synthesized successfully in ethanol by condensation of starting material 1-methyl-2-oxo-1,2-dihydroquinoline-3-carbaldehyde (1) with various substituted anilines (2a-j). The structure of the newly synthesized compounds was confirmed by proton (1H) and carbon (13C) nuclear magnetic resonance spectroscopy, Fourier transformation infrared (FT-IR), Mass spectroscopic study and elemental analysis. The in-vitro antimicrobial activity of the synthesized compounds was undertaken by agar well diffusion method against gram positive bacteria (Bacillus licheniformis and Bacillus cereus) gram negative bacteria (Escherichia coli and Acetobactor sp.) and antifungal activity against (Aspergillus Flavus and Pichnanomala). Further the compounds which shows good activity (3b, 3c, 3d, 3f, 3g and 3j) are screened for in-vitro antitubercular activity by Micro-plate alamar blue assay (MABA) method against mycobacterium tuberculosis H37Rv strain provided important information about activity against these strains. The structure activities of the synthesized compounds were also discussed. Compounds 3a, 3c, 3d, 3f and 3g show good argument with the different substituent attached to the phenyl ring.

Individual and combined effects of the dietary Spirulina platensis and Bacillus licheniformis supplementation on growth performance, antioxidant capacity, innate immunity, relative gene expression and resistance of goldfish, Carassius auratus to Aeromonas hydrophila

This study evaluated the individual and combined effects of the dietary Spirulina platensis (SP) and probiotic bacterium Bacillus licheniformis (BL) on the growth performance, immune responses, and disease resistance in goldfish (Carassius auratus). A total of 216 fish (3.39 ± 0.24 g) were randomly distributed in 12 tanks with 18 fish per tank (4 treatments with 3 replications) and fed with diets containing 0% S. platensis and B. licheniformis (T0), 108 CFU/g B. licheniformis (T1), 2.5% S. platensis (T2), and 108 CFU/g B. licheniformis + 2.5% S. platensis (T3(. There were no significant differences in growth parameters. The alternative complement pathway (ACH50) and lysozyme activity were significantly increased in T2 and T3 treatments. No marked differences were observed in total immunoglobulin and protease activity among treatments (P > 0.05). The relative expression of IGF-1 was not affected by experimental diets (P > 0.05). Ghrelin gene showed significantly higher mRNA levels in fish fed with SP and BL (P < 0.05). The relative expression of catalase (CAT), and glutathione reductase (GSR) significantly increased in fish fed with the SP and BL (P < 0.05). No marked difference in glutathione peroxidase (GPX) gene expression was seen between the treatments (P > 0.05). The mRNA levels of lysozyme, IL6, IL-1β, TGF, and TNF2 transcription were higher in fish fed with SP and BL (P < 0.05). No notable difference was observed in TNF1 and IL10 gene expression between treatments (P > 0.05). Moreover, the result of the challenge test with A. hydrophila showed that goldfish fed with SP and BL had a lower mortality rate than the control. In conclusion, the supplementation of SP and BL can be used as feed additives to enhance disease resistance against A. hydrophila infection by stimulating the immune system in goldfish.

Diagnostic Investigation of 100 Cases of Abortion in Sheep in Uruguay: 2015-2021.

The aim of this work was to identify causes of abortion through laboratory investigations in sheep flocks in Uruguay. One hundred cases of abortion, comprising 58 fetuses, 36 fetuses with their placentas, and 6 placentas were investigated in 2015–2021. Cases were subjected to gross and microscopic pathologic examinations, and microbiological and serological testing for the identification of causes of abortion, including protozoal, bacterial, and viral pathogens. An etiologic diagnosis was determined in 46 (46%) cases, including 33 (33%) cases caused by infectious pathogens, as determined by the detection of a pathogen along with the identification of fetoplacental lesions attributable to the detected pathogen. Twenty-seven cases (27%) were caused by Toxoplasma gondii, 5 (5%) by Campylobacter fetus subspecies fetus, and 1 (1%) by an unidentified species of Campylobacter. Fourteen cases (14%) had inflammatory and/or necrotizing fetoplacental lesions compatible with an infectious etiology. Although the cause for these lesions was not clearly identified, T. gondii was detected in 4 of these cases, opportunistic bacteria (Bacillus licheniformis, Streptococcus sp.) were isolated in 2 cases, and bovine viral diarrhea virus 1 subtype i (BVDV-1i) was detected in another. Campylobacter jejuni was identified in 1 (1%) severely autolyzed, mummified fetus. BVDV-2b was identified incidentally in one fetus with an etiologic diagnosis of toxoplasmosis. Microscopic agglutination test revealed antibodies against ≥1 Leptospira serovars in 15/63 (23.8%) fetuses; however, Leptospira was not identified by a combination of qPCR, culture, fluorescent antibody testing nor immunohistochemistry. Neospora caninum, Chlamydia abortus, Chlamydia pecorum, Coxiella burnetii and border disease virus were not detected in any of the analyzed cases. Death was attributed to dystocia in 13 (13%) fetuses delivered by 8 sheep, mostly from one highly prolific flock. Congenital malformations including inferior prognathism, a focal hepatic cyst, and enterohepatic agenesis were identified in one fetus each, the latter being the only one considered incompatible with postnatal life. Toxoplasmosis, campylobacteriosis and dystocia were the main identified causes of fetal losses. Despite the relatively low overall success rate in establishing an etiologic diagnosis, a systematic laboratory workup in cases of abortion is of value to identify their causes and enables zoonotic pathogens surveillance.

Effective treatment of aquaculture wastewater with mussel/microalgae/bacteria complex ecosystem: a pilot study

The discharge of aquaculture wastewater increased significantly in China. Especially, high content of nitrogen and phosphorus in wastewater could destroy the receiving water environment. To reduce the pollution of aquaculture wastewater, farmed triangle sail mussel (Hyriopsis cumingii) was proposed to be cultivated in the river. This was the first time that bacteria (Bacillus subtilis and Bacillus licheniformis) and microalgae (Chlorella vulgaris) were also used and complemented ecosystem functions. The pollutants in wastewater were assimilated by Chlorella vulgaris biomass, which was then removed through continuous filter-feeding of Hyriopsis cumingii. While, Bacillus subtilis and Bacillus licheniformis enhanced the digestive enzyme activities of mussel. It demonstrated that approximately 4 mussels/m3 was the optimal breeding density. Under such condition, orthogonal experiment indicated that the dose of Bacillus subtilis, Bacillus licheniformis, and Chlorella vulgaris should be 0.5, 1, and 2 mL respectively. Compared with mussel, mussel/microalgae, mussel/bacteria system, treatment ability of the mussel/microalgae/bacteria system in batch experiment was better, and 94.67% of NH3-N, 92.89% of TP and 77.78% of COD were reduced after reaction for 6 days. Finally, 90 thousand mussels per hectare of water were cultivated in Kulv river in China, and the field experiment showed that water quality was significantly improved. After about 35 days of operation, NH3-N, TN, TP and COD concentration were maintained around 0.3, 0.8, 0.3, and 30 mg/L respectively. Therefore, the mussel/microalgae /bacteria system in this study showed a sustainable and efficient characteristic of aquaculture wastewater bioremediation.

Bacillus licheniformis (MN900686) Mediated Synthesis, Characterization and Antimicrobial Potential of Silver Nanoparticles.

The use of bacteria in the synthesis of silver nanoparticles (AgNPs) emerges as an ecofriendly and exciting approach. In the present study, we reported the biosynthesis of AgNPs by using culture supernatant of the bacteria Bacillus licheniformis (MN900686). The biogenically synthesized AgNPs were confirmed by the change in the color of the culture filtrate from yellow to brown after the addition of AgNO3. Further characterization performed by means of UV vis-spectroscopy showed absorption peak at 414 nm which confirmed the formation of AgNPs. Fourier Transfer infrared (FTIR) confirmed the involvement of biological molecules in the formation of nanoparticles (NPs). The SEM revealed that the NPs have approximately 38 nm size. The agar well diffusion assay was used to determine antibacterial activity while tube dilution method was used to determine minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The human pathogenic bacterial strains i.e., P. aeruginosa (MN900691) and B. subtilis (MN900684), were used as test strains. The anti-bacterial assay against test strains revealed that these NPs showed concentration dependent increased zone of inhibition (ZOI). The maximum ZOI at 25 µL of AgNPs was 20 mm against B. subtilis after 24 hours of incubation. One-way ANOVA test showed significant ZOI (p ≤ 0.05) against B. subtilis. The MIC was ranged from 4.3-6.6 μg/mL while MBC ranged from 8.3 to 6.6 μg/mL. Overall, this study suggested that the biogenically synthesized NPs are an effective alternative source of antimicrobials against pathogenic bacteria.

Determination of Total Xylanase Activities of Various Thermophilic Bacteria

Enzymes, which have important metabolic functions in living organisms, make important contributions to human beings by using them for different purposes in many areas such as economy, food, agriculture, and industry as part of the daily lives. Today, enzymes, whose production and usage purposes, are increasing, were generally obtained from plant, animal, and microorganisms. In this study; the enzyme producing isolates and their total xylanase activities of various thermophilic bacteria (Bacillus coagulans, Bacillus licheniformis, Bacillus subtilis, Bacillus sp. and Geobacillus kaustophilus) isolated from previously hot springs in Eastern and Southeastern Anatolia regions were determined. In the enzyme activity of the isolates, 47 isolates showed xylanase activity less than 0.1 U/ml, 31 isolates were between 0.1 U/ml and 0.2 U/ml. However, 5 isolates of B. subtilis [BTX3 (0.206 U/ml), BTX6 (0.286 U/ml), BTX22 (0.2 U/ml), BTX27 (0.203 U/ml) and BTX32 (0.206 U/ml)] were exhibited highest activity for xylanase enzyme production.

Production and characterization of a novel thermostable laccase from Bacillus licheniformis VNQ and its application in synthesis of bioactive 1,4-naphthoquinones

Bacterial laccases have proven to be a potential biocatalyst for various industrial applications due to their remarkable catalytic and stability properties. In this study, a novel thermostable laccase was produced from the bacterium Bacillus licheniformis VNQ by submerged fermentation. The specific activity of crude and purified laccase was found to be 13.17U mg-1 and 83.47U mg-1, respectively. The enzyme possessed a molecular mass of ∼48kDa when characterized by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The optimum temperature and pH for enzyme activity was determined to be 55°C and 5.0, respectively. The enzyme was considered to be thermo-tolerant as it possessed a half-life of 4h at 70°C. The enzyme was utilized for the oxidative biotransformation of in situ synthesized p-quinones to biologically active compounds, 1,4-naphthoquinone and its derivative. The obtained products were characterized using nuclear magnetic resonance (NMR) spectroscopy and gas chromatography-mass spectrometry (GC-MS) analysis. A high yield of naphthoquinones (74.93±1.2%) with 1,4-naphthoquinone (60.61±1.0%), and its derivative 2-hydroxy-1,4-naphthoquinone (14.32±0.2%) was obtained at the optimized reaction conditions.

Communities of endophytic bacteria from Cereus peruvianus Mill. (Cactaceae) plants obtained from seeds and from in vitro-regenerated somaclone

Bioprospecting of endophytic microorganisms has been considered a promising resource for obtaining new biomolecules with biotechnological applications. Since few studies are available on the diversity of endophytic bacteria associated with species of the Cactaceae family, current analysis isolates and characterizes the communities of endophytic bacteria associated with the species of C. peruvianus grown in vivo obtained from seed and with somaclone of the same species regenerated in vitro to prospect for their plant-growth promoting activity. Isolation of endophytic bacteria from plants obtained from seeds and from regenerated somaclone in vitro identified nine species of endophytic bacteria (Moraxela osloensis, Corynebacterium mycetoides, Micrococcus luteus, Kocuria palustris, Staphylococcus epidermidis, Staphylococcus cohnii, Pseudomonas stuzeri, Bacillus licheniformis and Microbacterium sp.) not previously described in cacti, and signalized the somaclones as the most promising source of endophytic bacteria for obtaining new biomolecules with biotechnological applications. Somaclones are indicated as the most promising source of endophytic bacteria due to their high concentration of endophytes per gram identified in fresh somaclone tissue, the identification of the highest proportion endophytic bacteria, a source of IAA, and with the highest capacity of biological nitrogen fixation, and EPS production exclusively by the endophytic bacteria isolated from the in vitro regenerated somaclone.

Bioremediation of MP-polluted Waters Using Bacteria Bacillus licheniformis, Lysinibacillus massiliensis, and Mixed Culture of Bacillus sp. and Delftia acidovorans

Microplastic particles (MPs) are widely distributed pollutants in the environment. While a growing number of studies have shown that MPs are toxic to plant and animal life, systemic efforts to reduce their presence have been scarce. Low-density polyethylene (LDPE) and polystyrene (PS) are one of the most common among all plastic-forming MPs. In this study, pure bacterial strains, Bacillus licheniformis and Lysinibacillus &lt;br /&gt; massiliensis, and a mixed bacterial culture of Delftia acidovorans and Bacillus sp., were &lt;br /&gt; used for biodegradation of LDPE and PS microplastics. Biodegradation of MP-PS and &lt;br /&gt; MP-LDPE of particle size 300 – 500 μm was carried out under batch operating conditions at a temperature of 25 ± 2 °C, pH values of 7.15, and 160 rpm during 22 days. The &lt;br /&gt; obtained results showed that mixed bacterial cultures degraded MP-LDPE and MP-PS &lt;br /&gt; better than pure bacterial cultures, and the biodegradation efficiency was higher for MP-LDPE than for MP-PS, as indicated by greater reduction in peak intensity and spectral &lt;br /&gt; deformation, higher colony forming unit (CFU), and inorganic carbon (IC) values.

Isolation, molecular identification and enzyme activity of amylase producing thermophilic bacteria from hot springs

In this era, enzyme exploration in Indonesia continues to increase, and the amylase enzyme of about 30% of the total production is used worldwide. The great needs for amylase enzyme and its uses in several industrial and health fields lead to the search for potential natural resources in its production, including hot springs, which are very promising because of their thermophilic and thermostable properties. The aim of this study was to isolate, determine the activity and molecular identification of amylase-producing thermophilic bacteria from natural hot springs Dolok Tinggi Raja, Simalungun, North Sumatra. This study includes measurement of enzyme activity using the DNS method and molecular identification. The results were obtained from 20 isolated isolates, 6 isolates had amylase activity with the highest activity, namely the UTMTR VAR A10 isolate with an amylase enzyme activity of 0.2733 Unit/mL. Based on the molecular identification using 16SrRNA gene amplification based on the BLAST program and phylogenetic analysis with the MEGA X program, it was shown that the UTMTR VAR A10 isolate is a bacterium Bacillus licheniformis strain UTMTR VAR A10. Further research is needed to purify the enzyme in such a way that it can be applied to the industrial world.

Potential Application Of Bacillus Licheniformis Biosurfactant And Tofu Liquid Waste As Application Of MEOR

Energy is a basic human need which continues to increase every year. The fact is that the production of energy such as petroleum in Indonesia has decreased due to the depletion of petroleum reserves. The increasing consumption and increasing demand for energy has prompted the government to implement renewable energy planning. The solution that can be offered is Enhanced Oil Recovery (EOR) technology. Meanwhile, one of the developments in EOR technology that is environmentally friendly and able to increase oil recovery well is Microbial Enhanced Oil Recovery (MEOR). In the MEOR system, a bioproduct injection component called biosurfactant is used. The performance of biosurfactants in the system can be done by reducing the interface stress and mobilizing oil in the rock. The production of biosurfactants can be increased with the help of secretion of microorganisms. Based on the literature obtained, Bacillus licheniformis is a type of native bacteria that has the potential to produce biosurfactants with lipopeptide characteristics. Bacillus licheniformis is able to produce several extracellular enzymes, namely amylase, amino, peptidase, metal protease, lactamase, endo-N-acetyl glucosaminide and lipase. In addition, several studies have shown that Bacillus licheniformis has the potential to be applied to MEOR, bioremediation and industrial biotechnology. However, the biosurfactant produced from the bacterium Bacillus licheniformis requires a substrate to increase oil recovery. One type of organic substrate that can be used is tofu liquid waste. Tofu liquid waste contains high organic and nutrient materials consisting of 90.72% water, 1.8% protein, 1.2% fat, 7.36% crude fiber, and 0.32% ash. The author sees the potential use of tofu liquid waste because of its environmentally friendly nature. Therefore, the author offers an idea entitled The Potential Application of Bacillus Licheniformis Biosurfactant and Tofu Liquid Waste as an Application of MEOR Technology.

Draft Genome Sequence of Bacillus licheniformis Strain UASWS1606, a Plant Biostimulant for Agriculture.

Bacillus licheniformis is a well-known industrial bacterium. New strains show interesting properties of biostimulants and biological control agents for agriculture. Here, we report the draft genome sequence, obtained with an Illumina MiniSeq system, of strain UASWS1606 of the bacterium Bacillus licheniformis, which is being developed as an agricultural biostimulant.

Development of the zooplankton community in the growing ponds of the Novosibirsk region when growing carp fingerlings using the probiotic “Sibmos-PRO”

Quantitative characteristics of the zooplankton community in cyprinid growth ponds were studied. As a method of stimulating the growth and development of hydrobionts, the introduction of probiotic into water and feed was used. It was taken into account that zooplankton is the main and significant part of the natural food base for young carp grown in ponds. At the early stages of ontogenesis, the activity of digestive enzymes in carp is extremely low, the larva practically does not assimilate high-molecular compounds [7]. At the same time, zooplankton is a secondary link in the food chain of aquatic ecosystems, and plays an important role in their functioning and structure. Changes in plankton fauna can lead to modification of the aquatic ecosystem [18]. The development and existence of zooplankton pond communities during the growing season is influenced by a combination of abiotic and biotic factors, in particular: the composition and abundance of ichthyofauna, fluctuations in the water level in the reservoir, temperature, «flowering» of water, etc. Due to a set of indicators, and the strengthening or weakening of certain factors, it is possible to observe changes in the seasonal dynamics of zooplankton communities, which are more uneven than progressive. In the conducted research on the use of the probiotic Sibmos-Pro-antimicrobial feed concentrate based on mananoligosaccharides (obtained from yeast cell walls) in combination with the bacteria Bacillus Subtilis and Bacillus Licheniformis. Its introduction was carried out both in feed and in feed and water. Studies have shown that, judging by the productivity of carp and zooplankton biomass, the probiotic is absorbed by hydrobionts and affects the increase in the number and productivity of crustaceans. The level of development of the natural food supply increases, which ensures an increase in fish production. The structure of the zooplankton community changes under the influence of probiotics.

Usage of microbial combination degradation technology for the remediation of uranium contaminated ryegrass

Post phytoremediation accumulation of heavy metals in plants is causing an environmental issue worldwide. In this study, we investigated the ability of eight different kinds of microorganisms to degrade and release heavy metals from heavy metal enriched ryegrass, including 5 species of bacteria (Bacillus subtilis, Bacillus licheniformis, Bacillus pumilus-I, Bacillus pumilus-II and Bacillus cereus) and 3 of fungi (Phanerochaete chrysosporium, Trichoderma ressei and Pterula sp. strain QD-1), by growing them under uranium stress and assessing their ability to degrade biomass. After 30 days, the degradation ability of fungi was found better than that of bacteria, while the metal leaching ability of bacteria was found better. The highest degradation rate (upto 60%) was obtained by using P. chrysosporium, Pterula sp. strain QD-1 exhibited the best leaching rate for uranium (upto 77%). The overall degradation rate of lignin and cellulose and hemicellulose was found lower (40% and 60%, respectively). According to the antagonistic characteristics of microbes, we combined different dominant species, in which under optimal conditions the T2 combination (P. chrysosporium, T. reesei, and Pterula sp. strain QD-1 and B. subtilis) was able to degrade 80% of the ryegrass, 51% of lignin, 74% of cellulose and hemicellulose, releasing 78% of U, 90% of Pb and the releasing rate of other heavy metals was more than 95%. FTIR analysis showed the least degradation of lignin, while SEM-EDX analysis of the degradation residues displayed the microstructure of ryegrass being greatly damaged. Only a small amount of U was found in the residues of the researched combinations. This study provides efficient Microbial Combined Degradation Technology for heavy metal enriched biomass, which can effectively deal with heavy metal enriched plants, and provide a basis for the recovery and utilization of heavy metals, avoiding secondary pollution in the environment caused by this type of biomass.

Great Tit (Parus major) Uropygial Gland Microbiomes and Their Potential Defensive Roles.

The uropygial gland (preen gland) of birds plays an important role in maintaining feather integrity and hygiene. Although a few studies have demonstrated potential defensive roles of bacteria residing within these glands, the diversity and functions of the uropygial gland microbiota are largely unknown. Therefore, we investigated the microbiota of great tit (Parus major) uropygial glands through both isolation of bacteria (culture-dependent) and 16S rRNA amplicon sequencing (culture-independent). Co-culture experiments of selected bacterial isolates with four known feather-degrading bacteria (Bacillus licheniformis, Kocuria rhizophila, Pseudomonas monteilii, and Dermacoccus nishinomiyaensis), two non-feather degrading feather bacteria, one common soil bacterial pathogen and two common fungal pathogens enabled us to evaluate the potential antimicrobial properties of these isolates. Our results show major differences between bacterial communities characterized using culture-dependent and -independent approaches. In the former, we were only able to isolate 12 bacterial genera (dominated by members of the Firmicutes and Actinobacteria), while amplicon sequencing identified 110 bacterial genera (dominated by Firmicutes, Bacteroidetes, and Proteobacteria). Uropygial gland bacterial isolates belonging to the genera Bacillus and Kocuria were able to suppress the growth of four of the nine tested antagonists, attesting to potential defensive roles. However, these bacterial genera were infrequent in our MiSeq results suggesting that the isolated bacteria may not be obligate gland symbionts. Furthermore, bacterial functional predictions using 16S rRNA sequences also revealed the ability of uropygial gland bacteria to produce secondary metabolites with antimicrobial properties, such as terpenes. Our findings support that uropygial gland bacteria may play a role in feather health and that bacterial symbionts might act as defensive microbes. Future investigations of these bacterial communities, with targeted approaches (e.g., bacterial isolation and chemical analyses), are thus warranted to improve our understanding of the evolution and function of these host-microbe interactions.

Draft Genome Sequence of the Thermophilic Bacterium Bacillus licheniformis SMIA-2, an Antimicrobial- and Thermostable Enzyme-Producing Isolate from Brazilian Soil.

Bacillus licheniformis SMIA-2, a thermophilic and thermostable enzyme-producing bacterium, is found to be active against several strains of Staphylococcus aureus and several Bacillus species. Here, we report the 4.30-Mbp draft genome and bioinformatic predictions supporting gene inventories for amylase, protease, cellulase, xylanase, and antimicrobial compound biosynthesis.

Evidencing the uptake of electrons from X80 steel by Bacillus licheniformis with redox probe, 5-cyano-2,3-ditolyl tetrazolium chloride

Bioenergetic analysis implies that microorganisms can harvest the released energy from metal corrosion for survival via extracellular electron transfer (EET) under carbon-starvation conditions. In this work, we combined carbon starvation with CTC/DAPI counterstaining and developed a novel method for detecting EET from metal substrate to the cells. A wild-type nitrate-reducing bacterium (NRB) Bacillus licheniformis was evidenced to be able to take up electrons from the X80 steel substrate for respiration. This study provides reliable support to the bioenergetic theory for microbiologically influenced corrosion (MIC) of carbon steel by NRB.

Biomethane production improvement by enzymatic pre-treatments and enhancers of sewage sludge anaerobic digestion

Enzymatic hydrolysis is recognised as an effective pre-treatment for increasing biodegradability of sludge. In this work, isolated commercial enzymes as well as in-situ enzymes producer bacteria were used respectively as enhancers and pre-treatments of sewage sludge. Biodegradability of sample as well as biomethane potential production were studied. Results showed that depuration efficiencies in terms of CODs (73.5–85.5%) and TVS (28.5–42.7%) were more than twice the control value. In addition, pre-treated samples as well as enhanced samples with enzymes generated more biomethane than control. The optimal ones, were those with the isolated proteases (P) and with bacteria (Bacillus licheniformis) treatment in-situ (F), producing a total volume of 72.4 ± 2.62 ml CH4 and 114 ml ± 0.46 CH4, respectively, increasing the biogas volume in 3.65 and 5.77 times respectively compared with control.

Microbial levan and pullulan as potential protective agents for reducing adverse effects of copper on Daphnia magna and Vibrio fischeri

Microbial polysaccharides, due to their unique physiochemical properties, have found application in the food industry, cosmetics, pharmacy and medicine. In the environment, microbes can use polysaccharides to alleviate the adverse effects of heavy metals in their close proximity. This adaptive property shows interesting potential for bioremediation. Herein, the effects of the exopolysaccharides (EPS) levan, produced by the bacterium Bacillus licheniformis NS032 and pullulan, produced by the fungus Aureobasidium pullulans CH-1 in the presence of copper (Cu2+) have been investigated for the first time on antioxidant enzyme activity, respiration and Cu2+ bioaccumulation of Daphnia magna as well as the bioluminescence of Vibrio fischeri. Both EPS decreased toxicity of Cu2+ in the acute test with D. magna. The activity of catalase (CAT) was significantly diminished after acute exposure to Cu2+ in comparison to treatments with Cu2+ and EPS, while in the prolonged acute exposure the CAT activity did not show statistically significant (P ≤ 0.05) differences between treatments with and without the EPS. According to ICP-MS results, during prolonged acute exposure of neonates, the bioaccumulation of Cu2+ in treatments without the EPS was 52.03 μg/g of biomass (wet), while in treatments with EPS, the bioaccumulation was lower by one order of magnitude. The respiration of neonates during acute exposure to Cu2+ with or without the EPS was monitored using the MicroOxymax respirometer, and the results show the EPS can positively effect the respiration. In the case of bacterial bioluminescence, the toxicity of Cu2+ decreased in treatments with EPS (30 min EC10) from 3.54 mg/L to 140.61 mg/L (levan) and 45.00 mg/L (pullulan). This study demonstrates protective effect of EPS against Cu2+ toxicity on D. magna and V. fischeri, and opens the door for further investigation of potential application of levan and pullulan in bioremediation of heavy metals and mitigation of their adverse effects in the aquatic environment.