Biodegradation of toxic organic compounds using a newly isolated Bacillus sp. CYR2

The objective of this study was to isolate a new bacterium and investigate its ability for degradation of various toxic organic compounds. Based on 16S rRNA gene sequence and phylogenetic analysis, the isolated strain was identified as Bacillus sp. CYR2. Degradation of various toxic compounds and growth of CYR2 strain were evaluated with 2 and 4% inoculum sizes. All the experiments were conducted for 6 days, flasks were incubated at 30oC under 180 rpm. Among the 2 and 4% inoculum sizes, bacteria showed highest growth and toxic compounds degradation at 4% inoculum size. Especially, compared to 2% inoculum size, growth of the strain CYR2 at 4% inoculum size was increased by 15.1 folds with 4-secondarybutylphenol, 9.1 folds with phenol, and 5.4 folds with 4-tertiary-butylphenol. Strain CYR2 at 4% inoculum size showed highest removal of phenol (84 ± 5%), followed by 4-tertiary-butylphenol (66 ± 3%), 4-secondary-butylphenol (63 ± 5%) and 4-nonylphenol (57 ± 6%). Compared with 2% inoculum size, degradation ability of strain CYR2 with 4% inoculum size was enhanced by 3.45 times with 4-tertiary-octylphenol, and 2.53 times with 4-tertiarybutylphenol. Our results indicated that the newly isolated Bacillus sp. CYR2 can be used for in situ bioremediation of phenol and alkylphenols contaminated water

Enhanced extraction of heavy metals in the two-step process with the mixed culture of Lactobacillus bulgaricus and Streptococcus thermophilus

For biological extraction of heavy metals from chromated copper arsenate (CCA) treated wood, different bacteria were investigated. The extraction rates of heavy metals using Lactobacillus bulgaricus and Streptococcus thermophilus were highest. The chemical extraction rates were depended on the amounts of pyruvic acid and lactic acid. Especially, the extraction rates using mixed pyruvic acid and lactic acid were increased compared to those of sole one. They were also enhanced in the mixed culture of L. bulgaricus and S. thermophilus. To improve the extraction of CCA, a two-step processing procedure with the mixed culture of L. bulgaricus and S. thermophilus was conducted. A maximum of 93% of copper, 86.5% of chromium, and 97.8% of arsenic were extracted after 4 days. These results suggest that a two-step process with the mixed culture of L. bulgaricus and S. thermophilus is most effective to extract heavy metals from CCA treated wood

Isolation and characterization of a biosurfactant-producing heavy metal resistant Rahnella sp. RM isolated from chromium-contaminated soil

Objective of the study was to isolate heavy metal resistant bacteria from chromium-contaminated subsurface soil and investigate biosurfactant production and heavy metal bioremediation. Based on 16S rRNA gene sequence and phylogenetic analysis, the isolate was identified as Rahnella sp. RM. The biosurfactant production by heavy metal resistant Rahnella sp. RM was optimized using Box- Behnken design (BBD). The maximum emulsification activity was obtained 66% at 6% soybean meal in pH 7.0 and 33.5°C. The biosurfactant was characterized using Field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FT-IR) and matrix assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF). The highest metal removal rates using the biosurfactant were found 74.3, 72.5, and 70.1%, respectively, at the 100 mg/L amended flasks at 48 h. This study indicated the biosurfactant from heavy metal resistant Rahnella sp. RM could be used as a potential tool to remediate the metals in contaminated environments

Isolation of Bacillus sp. strains capable of decomposing alkali lignin and their application in combination with lactic acid bacteria for enhancing cellulase performance

Effective biological pretreatment method for enhancing cellulase performance was investigated. Two alkali lignin-degrading bacteria were isolated from forest soils in Japan and named CS-1 and CS-2. 16S rDNA sequence analysis indicated that CS-1 and CS-2 were Bacillus sp. Strains CS-1 and CS-2 displayed alkali lignin degradation capability. With initial concentrations of 0.05–2.0 g L−1, at least 61% alkali lignin could be degraded within 48 h. High laccase activities were observed in crude enzyme extracts from the isolated strains. This result indicated that alkali lignin degradation was correlated with laccase activities. Judging from the net yields of sugars after enzymatic hydrolysis, the most effective pretreatment method for enhancing cellulase performance was a two-step processing procedure (pretreatment using Bacillus sp. CS-1 followed by lactic acid bacteria) at 68.6%. These results suggest that the two-step pretreatment procedure is effective at accelerating cellulase performance

Isolation and characterization of tetrachloroethylene- and cis-1,2-dichloroethylene-dechlorinating propionibacteria

Two rapidly growing propionibacteria that could reductively dechlorinate tetrachloroethylene (PCE) and cis-1,2-dichloroethylene (cis-DCE) to ethylene were isolated from environmental sediments. Metabolic characterization and partial sequence analysis of their 16S rRNA genes showed that the new isolates, designated as strains Propionibacterium sp. HK-1 and Propionibacterium sp. HK-3, did not match any known PCE- or cis-DCE-degrading bacteria. Both strains dechlorinated relatively high concentrations of PCE (0.3 mM) and cis-DCE (0.52 mM) under anaerobic conditions without accumulating toxic intermediates during incubation. Cell-free extracts of both strains catalyzed PCE and cis-DCE dechlorination; degradation was accelerated by the addition of various electron donors. PCE dehalogenase from strain HK-1 was mediated by a corrinoid protein, since the dehalogenase was inactivated by propyl iodide only after reduction by titanium citrate. The amounts of chloride ions (0.094 and 0.103 mM) released after PCE (0.026 mM) and cis-DCE (0.05 mM) dehalogenation using the cell-free enzyme extracts of both strains, HK-1 and HK-3, were stoichiometrically similar (91 and 100%), indicating that PCE and cis-DCE were fully dechlorinated. Radiotracer studies with [1,2-¹⁴C] PCE and [1,2-¹⁴C] cis-DCE indicated that ethylene was the terminal product; partial conversion to ethylene was observed. Various chlorinated aliphatic compounds (PCE, trichloroethylene, cis-DCE, trans-1,2-dichloroethylene, 1,1-dichloroethylene, 1,1-dichloroethane, 1,2-dichloroethane, 1,2-dichloropropane, 1,1,2-trichloroethane, and vinyl chloride) were degraded by cell-free extracts of strain HK-1

Degradation of Toxic Compounds at Low and Medium Temperature Conditions Using Isolated Fungus

In the present study, a fungal strain isolated from the Antarctic soil was identified as Penicillium sp. CHY-2 based on its 5.8S rRNA gene sequence analysis. Furthermore, its biodegradation ability towards 13 different toxic compounds such as 4-butylphenol (4-BP), 4-sec-butylphenol (4-s-BP), 4-tert-butylphenol (4-t-BP), 4-nonylphenol (4-NP), 4-tert-octylphenol (4-t-OP), 4-chlorophenol (4-CP), phenol, bisphenol A (BPA), benzene, toluene, xylene, naphthalene, and phenanthrene at low (4°C) and medium (15°C) temperature conditions was evaluated using high pressure liquid chromatography. Among the 13 compounds, the strain CHY-2 effectively degraded the six compounds i.e., 4-BP, 4-s-BP, 4-t-BP, 4-NP, 4-CP, and phenol at 15°C within one week, and at 4°C within 3 weeks. Also CHY-2 effectively degraded the 4-t-OP at 15°C (70%), but not at 4°C (35%). Among different carbon sources tested, glucose was found to be the most suitable and the growth of CHY-2 at 4°C was slower than at 15°C. Addition of Tween 80 increased the growth and degradation ability of CHY-2 towards 4-BP at 4 and 15°C. The metabolites produced during the degradation of 4-BP were identified by gas chromatography-mass spectrometry. Also, bacteria present in the Antarctic soil were determined by denaturing gradient gel electrophoresis and the result showed the presence of Pseudomonas and Syntrophus groups of bacteria

Influence Of Disinfection On Bacterial Regrowth In Pilot Distribution System

A correlation between heterotrophic plate count (HPC) and chloramine residual in pilot distribution systems (PDSs) was investigated. The data was derived from an AWWARF (the Awwa Research Foundation) and Tampa Bay Water tailored collaboration project to determine the effect of blending different waters on distribution system water quality. Seven different finished waters were produced from surface, ground, or simulated brackish water sources on site and fed to 18 independent PDSs, either as a single finished water or as a blend of several finished waters. Significantly higher numbers for PDS HPC were observed below 0.06 mg/L of combined chlorine residual. Changes in assimilable organic carbon (AOC) levels between influent and effluent of the PDSs increased as disinfectant dosage decreased in distribution systems. Significant differences between input and output AOC (ΔAOC) were observed when the chloramine residual was less than 1.0 mg/L, and particularly when less than 0.5 mg/L. High HPC counts often occurred when chloramine residual was less than 0.5 mg/L, regardless of AOC levels or AOC stability. However AOC instability could occur at high influent AOC levels even in the presence of residual greater than 0.5 mg/L, with corresponding high HPC counts

Production of polyhydroxyalkanoates using sewage and cheese whey

Recently, polyhydroxyalkanoates (PHAs) have been produced using raw sewage in our laboratory; however, the production concentrations are low. Therefore, this study aimed to enhance PHA production by applying different strategies. PHA production was higher in sewage-containing medium than in mineral salt medium and was enhanced 22-fold after glucose supplementation. A relatively high degree of glucose consumption (83.6 ± 1.59 %) was also achieved. Bacteria incubated with cheese whey diluted with sewage showed higher PHA production than bacteria incubated with cheese whey diluted with distilled water did. The expression of the PHA synthase gene (phaC) was evaluated via real-time polymerase chain reaction using low- and high-carbon-containing sewage. Relatively higher phaC expression levels were observed in high-carbon-containing sewage but at lower nitrogen concentrations. The characteristics of the produced PHA were comparable to those of standard PHA. Therefore, this study revealed that the bacterium Bacillus sp. CYR1 can produce PHA from low- or high-carbon-containing wastewater

Quantification of the Monomer Compositions of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) and Poly(3-hydroxyvalerate) by Alkaline Hydrolysis and Using High-Performance Liquid Chromatography

With the growing interest in bioplastics, there is an urgent need to develop rapid analysis methods linked to production technology development. This study focused on the production of a commercially non-available homopolymer, poly(3-hydroxyvalerate) (P(3HV)), and a commercially available copolymer, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (P(3HB-co-3HV)), through fermentation using two different bacterial strains. The bacteria Chromobacterium violaceum and Bacillus sp. CYR1 were used to produce P(3HV) and P(3HB-co-3HV), respectively. The bacterium Bacillus sp. CYR1 produced 415 mg/L of P(3HB-co-3HV) when incubated with acetic acid and valeric acid as the carbon sources, whereas the bacterium C. violaceum produced 0.198 g of P(3HV)/g dry biomass when incubated with sodium valerate as the carbon source. Additionally, we developed a fast, simple, and inexpensive method to quantify P(3HV) and P(3HB-co-3HV) using high-performance liquid chromatography (HPLC). As the alkaline decomposition of P(3HB-co-3HV) releases 2-butenoic acid (2BE) and 2-pentenoic acid (2PE), we were able to determine the concentration using HPLC. Moreover, calibration curves were prepared using standard 2BE and 2PE, along with sample 2BE and 2PE produced by the alkaline decomposition of poly(3-hydroxybutyrate) and P(3HV), respectively. Finally, the HPLC results obtained by our new method were compared using gas chromatography (GC) analysis.Validerad;2023;Nivå 2;2023-06-08 (joosat);Funder: Japan Science and Technology Agency (VP29117937927); Japan Society for the Promotion of Science (JSPS) (P15352); Ogasawara Foundation for the Promotion of Science Engineering;Part of Special Issue: Advances in Polyhydroxyalkanoate (PHA) Production, Volume 4Licens fulltext: CC BY License</p