Soil washing of total petroleum and polycyclic aromatic hydrocarbons from crude oil-contaminated ultisol using aqueous extracts of waterleaf.

Ultisols are acidic soils found in humid climates and are known for poor fertility. Crude oil impacted ultisols, therefore, require special treatment measures to account for nutrient loss during treatment. In this paper, we report the utilization of a food waste, aqueous extracts of waterleaf (Talinum triangulare), as a plant-derived surfactant to wash simulated crude oil-contaminated soils. The soils before and after washing were monitored for microbial loads, nutrient parameters, physicochemical characteristics, total petroleum hydrocarbons (TPHs) and polycyclic aromatic hydrocarbons (PAHs). Although higher amounts of PAHs (up to 100%) were removed compared to TPHs (up to 95.7%), the results revealed that the efficiency of the waterleaf extracts was comparable to that of a commercial surfactant sodium dodecyl sulphate. However, soils washed with the waterleaf extracts retained some significant amounts of nutrients and favourable pH moderation. In both surfactants, soil microbial loads reduced significantly. Overall, the aqueous waterleaf extracts showed potential as ecofriendly surfactants and nutrients retainer during soil washing of contaminated ultisols.

Stochastic modeling and meta-heuristic multivariate optimization of bioprocess conditions for co-valorization of feather and waste frying oil toward prodigiosin production.

Serratia marcescens strain UCCM 00009 produced a mixture of gelatinase and keratinase to facilitate feather degradation but concomitant production of prodigiosin could make waste feather valorization biotechnologically more attractive. This article describes prodigiosin fermentation through co-valorization of waste feather and waste frying peanut oil by S. marcescens UCCM 00009 for anticancer, antioxidant, and esthetic applications. The stochastic conditions for waste feather degradation (WFD), modeled by multi-objective particle swarm-embedded-neural network optimization (ANN-PSO), revealed a gelatinase/keratinase ratio of 1.71 for optimal prodigiosin production and WFD. Luedeking-Piret kinetics revealed a non-exclusive, non-growth-associated prodigiosin yield of 9.66 g/L from the degradation of 88.55% waste feather within 96 h. The polyethylene glycol (PEG) 6000/Na+ citrate aqueous two-phase system-purified serratiopeptidase demonstrated gelatinolytic and keratinolytic activities that were stable for 240 h at 55 °C and pH 9.0. In vitro evaluations revealed that the prodigiosin inhibited methicillin-resistant Staphylococcus aureus at IC50 of 4.95 µg/mL, the plant-pathogen, Sclerotinia sclerotiorum, at IC50 of 2.58 µg/mL, breast carcinoma at IC50 of 0.60 µg/mL and 2,2-diphenyl-1-picryl-hydrazyl hydrate (DPPH) free-radical at IC50 of 96.63 µg/mL). The pigment also demonstrated commendable textile dyeing potential of fiber and cotton fabrics. The technology promises cost-effective prodigiosin development through sustainable waste feather-waste frying oil co-management.

A novel strain of Stenotrophomonas acidaminiphila produces thermostable alkaline peptidase on agro-industrial wastes: process optimization, kinetic modeling and scale-up.

Bacterial alkaline peptidases, especially from Bacillus species, occupy the frontline in global enzyme market, albeit with poor production economics. Here, we report the deployment of response surface methodology approximations to optimize fermentation parameters for enhanced yield of alkaline peptidase by the non-Bacillus bacterium; Stenotrophomonas acidaminiphila. Shake flask production under optimized conditions was scaled up in a 5-L bench-scale bioreactor. Logistic and modified Gompertz models revealed significant fits for biomass formation, total protein, and substrate consumption models. Maximum specific growth rate (µmax = 0.362 h-1) of the bacterium in the optimized medium did not differ significantly from those in Luria-Bertani and trypticase soy broths. The aqueous two-phase system-purified 45.7 kDa alkaline protease retained 83% activity which improved with increasing sodium dodecyl sulfate concentration thus highlighting potential laundry application. Maximum enzyme activity occurred at 75ºC and pH 10.5 but was inhibited by 5 mM phenyl-methyl-sulfonyl fluoride suggesting a serine-protease nature.

Occurrence and spatial distribution of heavy metals in landfill leachates and impacted freshwater ecosystem: An environmental and human health threat.

Municipal landfill leachates are a source of toxic heavy metals that have been shown to have a detrimental effect on human health and the environment. This study aimed to assess heavy metal contamination in leachates, surface water, and sediments from non-sanitary landfills in Uyo, Nigeria, and to identify potential health and environmental effects of leachate contamination. Over the wet and dry seasons, surface water and sediment samples were collected from an impacted freshwater ecosystem, and leachates samples from six monitoring wells. Elemental analyses of samples were conducted following standard analytical procedures and methods. The results indicated that leachate, surface water, and sediment samples all had elevated levels of heavy metals, implying a significant impact from landfills. Pollution indices such as the potential ecological risk index (PERI), pollution load index (PLI), degree of contamination (Cd), modified degree of contamination (mCd), enrichment factor (EF), geoaccumulation index (Igeo), and Nemerov pollution index (NPI) were used to assess the ecological impacts of landfill leachates. The following values were derived: PERI (29.09), PLI (1.96E-07), Cd (0.13), mCd (0.16), EF (0.97-1.79E-03), Igeo (0), and NPI (0.74). Pollution indicators suggested that the sediment samples were low to moderately polluted by chemical contaminants from the non-sanitary landfills, and may pose negative risks due to bioaccumulation. Human health risks were also assessed using standard risk models. For adults, children, and kids, the incremental lifetime cancer rate (ILCR) values were within the acceptable range of 1.00E-06-1.00E-04. The lifetime carcinogenicity risks associated with oral ingestion exposure to heavy metals were 9.09E-05, 1.21E-05, and 3.60 E-05 for kids, adults, and children, respectively. The mean cumulative risk values for dermal exposures were 3.24E-07, 1.89E-06, and 1.17E-05 for adults, children, and kids, respectively. These findings emphasized the risks of human and biota exposure to contaminants from landfills.

Bioprocess Optimization of Nutritional Parameters for Enhanced Anti-leukemic L-Asparaginase Production by Aspergillus candidus UCCM 00117: A Sequential Statistical Approach.

Sequential optimization of bioprocess nutritional conditions for production of glutaminase-near-free L-asparaginase by Aspergillus candidus UCCM 00117 was conducted under shake flask laboratory conditions. Catalytic and anti-cancer activities of the poly-peptide were evaluated using standard in vitro biochemical methods. Medium nutrients were selected by one-factor-at-a-time (OFAT) approach while Plackett-Burman design (PBD) screened potential factors for optimization. Path of steepest ascent (PSA) and response surface methodology (RSM) of a Min-Run-Res V fractional factorial of a central composite rotatable design (CCRD) were employed to optimize factor levels towards improved enzyme activity. A multi-objective approach using desirability function generated through predictor importance and weighted coefficient methodology was adopted for optimization. The approach set optimum bioprocess conditions as 49.55 g/L molasses, 64.98% corn steep liquor, 44.23 g/L asparagine, 1.73 g/L potassium, 0.055 g/L manganese and 0.043 g/L chromium (III) ions, at a composite desirability of 0.943 and an L-asparaginase activity of 5216.95U. The Sephadex-200 partially-purified polypeptide had a specific activity of 476.84 U/mg; 0.087U glutaminase activity, 36.46% yield and 20-fold protein purification. Anti-cancer activity potentials of the catalytic poly-peptide were dose-dependent with IC50 (µg/mL): 4.063 (HL-60), 13.75 (HCT-116), 15.83 (HeLa), 11.68 (MCF-7), 7.61 (HepG-2). The therapeutic enzyme exhibited 15-fold more cytotoxicity to myeloid leukemia cell line than to normal (HEK 238 T) cell. Optimum temperature and pH for activity were within physiological range. However, significant interactions between exposure time and levels of each of temperature and pH made interpretations of residual enzyme activities difficult. The manganese-dependent L-asparaginase from Aspergillu s candidus UCCM 00117 is recommended for further anticancer drug investigations.

Bioaccumulation and cancer risk of polycyclic aromatic hydrocarbons in leafy vegetables grown in soils within automobile repair complex and environ in Uyo, Nigeria.

Using gas chromatography-mass spectrometry and an incremental lifetime cancer risks (ILCRs) assessment model, the bioaccumulation and cancer risk of 16 USEPA priority polycyclic aromatic hydrocarbons (PAHs) in leafy vegetables (Vernonia amygdalina and Lasianthera africanum) grown in soils within an automobile repair complex environment in Uyo, Nigeria was studied. The total PAHs concentrations recorded for soils ranged from 0.02 to 1.77 mg/kg. The highest level of 1.77 mg/kg was recorded for soils from the main automobile repair complex (site 1). Low molecular weight (LMW) PAHs were predominant although some high molecular weight (HMW) PAHs suites (0.04 mg/kg of chrysene and 0.04 of benzo[k]fluoranthene) were also found in site 1. The leafy vegetables accumulated PAHs were mostly LMW. Accumulation levels were similar but the extent of PAH uptake in vegetables was species dependent as V. amygdalina accumulated more (0.81 mg/kg). The bioaccumulation factors (BaFs) calculated ranged from 0.22 to 0.63 for L. africanum, and 0.18 to 0.55 for V. amygdalina in site 1 where high PAH levels were recorded in soil. Pearson correlation coefficient analysis revealed a strong positive relation between the PAH content of soil and the amount accumulated by L. africanum (r = 0.5) and V. amygdalina (r = 0.8) at p = 0.05. The vegetable's potential to bioaccumulate PAHs is indicative of their use as good bioindicators for PAH contamination in soil. Only two of the USEPA possible human carcinogenic PAHs were detected, and carcinogenic risk assessment based on occupational exposures to soil particles by adults revealed that the total risk level (7.17 × 10-5) contribution from incidental soil ingestion, dermal contact, and soil particle dust inhalation slightly exceed the USEPA acceptable limits (< 1.00 × 10-5). There is a need for public education on consumption of vegetables grown in and around automobile repair complexes across Nigeria.

Polycyclic aromatic hydrocarbons loads and potential risks in freshwater ecosystem of the Ikpa River Basin, Niger Delta-Nigeria.

In this study, the levels of 16 USEPA-prioritized polycyclic aromatic hydrocarbons (PAHs) were quantified in various environmental matrices in Ikpa River Basin and nearby dumpsites using gas chromatography-mass spectrometry (GC-MS). The levels of the contaminants were further subjected to models to estimate possible sources and potential risks. The results obtained revealed that nearby dumpsites could be the major source of contamination of the Ikpa River Basin. The total sum of PAHs in water and sediment samples gave 926.6 µg/l and 1099.7 µg/kg, respectively. Higher concentrations, 3025.8 µg/kg, 3645.7 µg/kg, and 2457.2 µg/l, were recorded for nearby municipal dumpsite soil, hospital dumpsite soil, and landfill leachates, respectively. Hierarchical cluster analysis (HCA) and PAH molecular diagnostic ratios (MDRs) suggest that PAH loading in the river basin were mostly of pyrogenic origin. The risk assessment indicated that exposure to PAHs through dermal contact with sediments was most significant than oral ingestion of water and children were the most vulnerable group. Non-cancer (toxic) risks due to exposure to PAHs by oral ingestion of water from Ikpa River were within acceptable limits as the calculated hazard quotients (HQs) and hazard indexes (HIs) were below unity, suggesting negligible or no toxic risk. However, toxic risks through dermal contact with sediments reached unacceptable limits as HI values exceeded unity for all sample stations. Estimated cancer risks due to oral ingestion of water reached the USEPA minimum risk level (3.14 × 10(-5)) requiring public notification while risks due to dermal adsorption of PAHs from the sediments reached levels (2.10 × 10(-1)) requiring remediation actions.

Occurrence and distribution of polycyclic aromatic hydrocarbons in surface microlayer and subsurface seawater of Lagos Lagoon, Nigeria.

Polycyclic aromatic hydrocarbons (PAHs) in surface microlayer (SML) and subsurface water (SSW) of Lagos Lagoon were investigated using gas chromatography-electron capture detector (GC-ECD) technique to ascertain their occurrence and spatial distribution, origin, enrichment, and carcinogenicity. Total PAH (ΣPAH) concentrations ranged from 9.10 to 16.20 µg L(-1) in the SML and 8.90 to 13.30 µg L(-1) in the SSW. ΣPAH concentrations were relatively higher in the SML than the underlying SSW samples. The enrichment factors (EFs) of ΣPAHs ranged from 0.76 to 1.74 while the EFs of the individual PAHs varied from 0.50 to 2.09. In general, the EFs values calculated in this study were consistent or slightly less than the EFs reported for similar coastal seawater ecosystems. A correlation between the EFs of fluoranthene and pyrene indicated a positive significant value (R = 0.9828, p < 0.0001, n = 6). Source analyses using the phenanthrene/anthracene and fluoranthene/pyrene ratios indicated the dominance of petrogenic-derived PAHs. Furthermore, enhanced concentrations of BaP (strong carcinogenicity) in SML and SSW samples, which resulted in higher EFs, could pose serious ecological and human health risks.