Optimizing concentration and interaction mechanism of Demodesmus sp. and Achromobacter pulmonis sp. consortium to evaluate their potential for dibutyl phthalate removal from synthetic wastewater.

A green approach of Desmodesmus sp. to Achromobacter pulmonis (1:1) coculture ratios was optimized to improve the removal efficiency of dibutyl phthalate (DBP) from simulated wastewater. High DBP resistance bacterial strains and microalgae was optimized from plastic contaminated water and acclimation process respectively. The influence of various factors on DBP removal performance was comprehensively investigated. Highest DBP removal 93 % was recorded, when the ratios algae-bacteria 1:1, with sodium acetate, pH-6, shaking speed-120 rpm and lighting periods L:D-12:12. Enough nutrient (TN/TP/TOC) availability and higher protein-108 mg/L and sugar-40 mg/L were observed in presences of 50 mg/L DBP. The degradation and sorption were calculated 81,12; 27,39 & 43,12 % in algae-bacteria, only algae and only bacteria system respectively. The degradation kinetics t1/2 3.74,22.15,12.86 days were evaluated, confirming that algae-bacteria effectively degrade the DBP. This outcome leading to promote a green sustainable approach to remove the emerging contamination from wastewater.

Measuring the effects of diethyl phthalate microplastics on marine algae growth using dielectric spectroscopy.

This paper presents the development of a dielectric spectroscopy-based method using a customized, transmission line probe, fabricated on a printed circuit board (PCB), for monitoring the effect of diethyl phthalate (DEP) microplastics on marine algae growth. Experiments were performed by exposing marine algae (Chlorella pyrenoidosa) to DEP (0-50 mg) for up to 6 days. In order to amplify the electrophysiological effects and improve the sensing, a glutaraldehyde crosslinking agent was used and encapsulated on the surface of the probe. The reflection coefficient (S11) and the complex permittivity (ɛ' & ɛ″) of the Medium Under Test (MUT) were investigated in the frequency range of 30 kHz-800 MHz. Without the presence of DEP, the number of algae (104 cells/mL) and chlorophyll content (mg/L) increased at the rates of 207.73 × 104 cells/mL and 148.1 mg/L per day, respectively. After 6 days of exposing Chlorella pyrenoidosa (C. pyrenoidosa) algae to different DEP concentrations, the growth rate decreased down to -11.92 × 104 cells/mL and -19.19 mg/L (50 mg DEP), respectively. Additionally, the linearity of the relationship kept decreasing as the DEP content increased from R2 = 0.9716 to R2 = 0.1050 and from R2 = 0.9293 to R2 = 0.4961, respectively. Dielectric spectroscopy using the custom, transmission line probe, at 740 MHz, showed linear relationship (-1.22 dB/day) between the reflection coefficient (S11) and hence complex permittivity (ɛ' & ɛ″) without the presence of DEP. However, as the DEP content increased, algae growth was prohibited more intensely, shown both from the number of algae and the chlorophyll content. This trend was reflected on S11 and subsequently on the complex permittivity. This relationship confirms the capability of this method to monitor the growth of marine algae in almost real-time. This dielectric spectroscopy method could be a potential, low-cost tool to examine the impact of microplastic pollutants on marine microorganisms.

A green approach to copper biodetoxification and sustainable agriculture application by vermicomposting in pig manure.

A green approach of copper (Cu) contaminated pig manure composting by earthworm Eisenia fetida was optimized. This work aims to assess the relationship between the bio-fertility properties and bioaccumulation of Cu during vermicomposting with five different doses of Cu. The optimal concentration of copper largely promoted the enrichment of nitrogen, phosphorus, and potassium, but the biological activities of earthworms could be inhibited once the Cu concentration exceed the threshold. When the Cu doses at 300 mg kg-1, the nutrient recovery rate (Irecovery) of available nitrogen, phosphorus and potassium reached their highest value, concomitant with largest C/N ratio reduced at 46.01 %. Moreover, nutrients recovery mechanism of total phosphorus increased up to 0.11 % h-1 and higher bioaccumulations in faces and intestine were detected by 1.79 and 0.99, respectively, during vermicomposting. The maximal enzyme activity rates (kmax) indicate that the enzyme activities, such as ROS and SOD, are sensitive bioindicators, which can be used to estimate the stress response of earthworms and Cu biotoxicity. The maximum specific growth rate (µmax) of the actinomycetes (TAct) increased gradually from 0.02 to 0.04 with the increase of Cu doses, but total fungi (TF) showed different response to µmax, which decreased firstly and then increased. It was demonstrated that Cu influenced the gut microbial community to vary the bio-fertility properties and bioaccumulation of Cu in the pig manure. All the findings refer that the vermicomposting could be the sustainable agricultural practices.

Study on the management efficiency of lanthanum/iron co-modified attapulgite on sediment phosphorus load.

Attapulgite co-modified by lanthanum-iron (MT-LHMT) was used to study its effectiveness and mechanism in controlling phosphorus release from sediments. MT-LHMT has high adsorption capacity for phosphate and the maximum adsorption capacity of MT-LHMT to phosphate can reach 75.79 mg/g. The mechanism mainly involved electrostatic action, surface precipitation and ligand exchange between MT-LHMT bonded hydroxyl and phosphate to form La-O-P and Fe-O-P inner-sphere complexes. MT-LHMT has excellent adsorption performance in the pH range of 3-8. In addition to HCO3-, CO32- and HA- had a negative effect on the phosphorus removal of MT-LHMT, while NO3-, Cl-, SO42-, K+, Ca2+ and Mg2+ had a positive or no effect on phosphorus removal. MT-LHMT significantly reduced the risk of phosphorus release from overlying water in different dose effects and covering methods, as well as the unstable inactivation of flowing phosphorus, sediment dissolved reactive phosphorus (DRP) and available phosphorus with medium diffusion gradient in thin film in the sediment-water interface (Labile-PDGT). The MT-LHMT capping wrapped with fabric can reduce the risk of nitrogen release from sediment to overlying water more than only MT-LHMT capping. The results of this study showed that the MT-LHMT capping wrapped with fabric has high potential and can be used as an active capping material to manage the nitrogen and phosphorus load in surface water.

Isolating Fistulifera pelliculosa from the northern Bohai Sea and analyzing biochemical composition, antibacterial and nutrient removal potential.

The microalgae located near the estuary of the Liaohe River along the coast of Panjin have long been in an area with large fluctuations in salinity, temperature, and nutrients, and have high-quality alternatives for high-value metabolites. Three strains of microalgae were screened and the biomass of microalgae could be optimized 0.313-0.790 g L-1 in 10 L bioreactor. The determination results of bioactive substances in these three microalgae showed that, the amount of fucoxanthin in the growth phase II (14 days) was maximum, at 5.354, 6.284 and 14.837 mg g-1 respectively. The diatoxanthin of Dut-wj-J1 in growth phase III (21 days) could reach 5.158 mg g-1. Dut-wj-J4 had the highest lipid production efficiency (9.45 mg L-1 d-1) followed by Dut-wj-J2 (8.49 mg L-1 d-1) and Dut-wj-J1 (8.18 mg L-1 d-1) respectively. These bioactive substances have inhibition zones of 7-13 mm against all four strains of bacteria ie., Acetobacter, Rhodococcus erythropolis, Escherichia coli and Bacillus subtilis Cohn respectively. In addition, these microalgae can play a potential role in nutrient enrichment in eutrophic seawater. The NO3- degradation rates of these three algae in the first 14 days were 75.0 %, 45.8 % and 100 % respectively, as well as the PO4- degradation rates in the first 7 days were 94.8 %, 100 % and 80.9 % respectively. This work manifests the plasticity of algae isolated from the Bohai Sea and provides useful insights for further joint production of bioactive substances.

Enhanced removal of tetracycline from synthetic wastewater using an optimal ratio of co-culture of Desmodesmus sp. and Klebsiella pneumoniae.

A sustainable approach of Desmodesmus sp. GIEC-179: Klebsiella pneumoniae (DUT-XJR-t-1.2) co-culture ratios were optimized to remove tetracycline (TET) from synthetic wastewater. To enhance the tetracycline removal performance, the effect of microalgae-bacterial co-culture ratio, maximum TET concentration, effective inoculum amount, growth temperature and pH were studied. The optimized ratio 1:2 of Desmodesmus sp.: K. pneumoniae showed the optimal removal percentage at the temperature of 25 °C, pH 7 and 10% inoculum amount; and the removal of TET was recorded as 95%. Moreover, this study explored the Desmodesmus sp.: K. pneumoniae (1:2) nutrient (COD, NH4+ and PO43-) exchange relationship and their interaction of TET removal to better understand their fundamental mechanism. According to the results of this study, Desmodesmus sp.: K. pneumoniae co-culture could be a green option for bio-removal of tetracycline from wastewater.

Debottlenecking Thermophilic Cyanobacteria Cultivation and Harvesting through the Application of Inner-Light Photobioreactor and Chitosan.

Thermophilic cyanobacteria are a low-carbon environmental resource with high potential thanks to their innate temperature tolerance and thermostable pigment, phycocyanin, which enhances light utilisation efficiency and generates a high-value product. However, large-scale cultivation and harvesting have always been bottlenecks in unicellular cyanobacteria cultivation due to their micrometric size. In this study, a 40-litre inner-light photobioreactor (PBR) was designed for scaled-up cultivation of Thermosynechococcus elongatus E542. By analysing light transmission and attenuation in the PBR and describing it via mathematical models, the supply of light energy to the reactor was optimised. It was found that the hyperbolic model describes the light attenuation characteristics of the cyanobacterial culture more accurately than the Lambert-Beer model. The internal illumination mode was applied for strain cultivation and showed a two-fold better growth rate and four-fold higher biomass concentration than the same strain grown in an externally illuminated photobioreactor. Finally, the downstream harvesting process was explored. A mixture of chitosan solutions was used as a flocculant to facilitate biomass collection. The effect of the following parameters on biomass harvesting was analysed: solution concentration, flocculation time and flocculant concentration. The analysis revealed that a 4 mg L-1 chitosan solution is optimal for harvesting the strain. The proposed solutions can improve large-scale cyanobacterial biomass cultivation and processing.

Investigating the potentiality of Scenedesmus obliquus and Acinetobacter pittii partnership system and their effects on nutrients removal from synthetic domestic wastewater.

A lab-scale study of Scenedesmus obliquus: Acinetobacter pittii (S. obliquus: A. pitti) partnership cultured in synthetic domestic wastewater was conducted to evaluate the partnership performance for growth and removal of nutrients from wastewater. To draw out the functional dependencies of this partnership measured the ammonia-nitrogen (NH4+-N), ortho-phosphate (PO43--P), soluble total phosphorus (TP), chemical oxygen demand (COD) and have got the nutrient removal rate of 85.90%, 91.50%, 73.75% and 100% respectively. The results showed that their optimized partnership ratio is 2:1 for S. obliquus: A. pitti and, CO2 & O2 exchanges in between was the more crucial parameters to shifting the best nutrient removals performance and promoted biomass quantity.

Exploring an in situ LED-illuminated isothermal micro-calorimetric method to investigating the thermodynamic behavior of Chlorella vulgaris during CO2 bio-fixation.

Much endeavor has been dispensed recently to evaluate the potential of CO2 mitigation by microalgae. We introduce an alternative, novel, LED-illumination isothermal microcalorimetric method to assess the thermodynamic behaviors of microalgae for better understanding of their carbon sequestration capacity. Microalgae thermodynamic behaviors were recorded as power-time curves, and their indices such as total heat evolution (QT), maximum power output (Pmax) and heat generated by per algae cell (JN/Q) were obtained. The values for highest (74.80 g L-1) and control sample (0.00 g L-1) of QT, Pmax and JN/Q were 20.85 and 2.32 J; 252.17 and 57.67 µW; 7.91 × -06 and 8.80 × -07 J cell-1, respectively. According to the values of QT, a general order to promote the CO2 sequestration was found at 74.8 g L-1 > 29.92 g L-1 > 14.96 g L-1 > 7.48 g L-1 > 0 g L-1 of C sources, which directly corresponded to carbon availability in the growth medium. Chlorella vulgaris GIEC-179 showed the highest peak Pmax at 74.8 g L-1 concentration which was directly transformed to their biomass during bio-fixation of CO2 process. This study is applicable for better understanding of CO2 fixation performance of algae.

High-frequency, dielectric spectroscopy for the detection of electrophysiological/biophysical differences in different bacteria types and concentrations.

This paper describes a novel technique to quantify and identify bacterial cultures of Bacillus Subtilis (2.10-1.30 × 109 CFU mL-1) and Escherichia Coli (1.60-1.00 × 109 CFU mL-1), in corn oil using dielectric spectroscopy at elevated frequencies of 0.0100-20.0 GHz. This technique is using the electrophysiological/biophysical differences (e.g. gram positive and gram negative) between various bacteria types, as a basis to distinguish between bacteria concentrations and bacteria types. A close-ended, coaxial probe of 20.0 mm long sample-holder was developed and used to calculate the dielectric constant from the measured S parameters of the bacterial cultures, using the Nicolson-Ross-Weir method. This technique shows a linear relationship (r2 ≥ 0.999) between the dielectric constant and the cell concentration, at 16.0 GHz. The sensitivity of the technique is 0.177 × 109 (CFU mL-1)-1 for B. Subtilis (with a size of 10.0 × 1.00 µm), 0.322 × 109 (CFU mL-1)-1 for E. Coli (with a size of 2.00 × 0.500 µm) and 0.913 × 109 (CFU mL-1) -1 for their 1:1 mixture, while the response time is 60.0s. The dependency of dielectric constant on the bacterial cell concentration at a given frequency can be potentially exploited for measuring bacterial concentrations and biophysical differences.

Characterization of green synthesized nano-formulation (ZnO-A. vera) and their antibacterial activity against pathogens.

The application of nanotechnology in medicine has recently been a breakthrough in therapeutic drugs formulation. This paper presents the structural and optical characterization of a new green nano-formulation (ZnO-Aloe vera) with considerable antibacterial activity against pathogenic bacteria. Its particle structure, size and morphology were characterized by XRD, TEM and SEM. And optical absorption spectra and photoluminescence were measured synchronously. Their antibacterial activity against Escherichia coli and Staphylococcus aureus was also investigated using thermokinetic profiling and agar well diffusion method. The nano-formulation is spherical shape and hexagonal with a particle size ranging from 25 to 65 nm as well as an increased crystallite size of 49 nm. For antibacterial activity, the maximum inhibition zones of ZnO and ZnO+A. vera are 18.33 and 26.45 mm for E. coli, 22.11 and 28.12 mm for S. aureus (p<0.05). Considering Pmax, Qt and k, ZnO+A. vera nano-formulation has a significant (p < 0.05) antibacterial effect against S. aureus almost at all concentration and against E. coli at 15 and 25mg/L. ZnO+A. vera nano-formulation is much more toxic against S. aureus than E. coli, with an IC50 of 13.12 mg/L and 21.31 mg/L, respectively. The overall results reveal that the ZnO-A. vera nano-formulation has good surface energy, crystallinity, transmission, and enriched antibacterial activities. Their antibacterial properties are possibly relevant to particle size, microstructural ionization, the crystal formation and the Gram property of pathogens. This ZnO-A. vera nano-formulation could be utilized effectively as a spectral and significant antibacterial agent for pathogens in future medical and environmental concerns.

Development and analytical application of a glucose biosensor based on glucose oxidase/O-(2-hydroxyl)propyl-3-trimethylammonium chitosan chloride nanoparticle-immobilized onion inner epidermis.

A glucose biosensor comprising a glucose oxidase/O-(2-hydroxyl)propyl-3-trimethylammonium chitosan chloride nanoparticle (O-HTCC NP)-immobilized onion inner membrane and a dissolved oxygen (O(2)) sensor has been successfully developed. The detection scheme is based on the depletion of dissolved O(2) content upon exposure to glucose. The decrease in O(2) level was monitored and related to the glucose concentration. The biosensor shows linear response to glucose from 0.0 to 0.60 mM with a detection limit of 50 microM (S/N=3). The effect of O-HTCC NP and enzyme loading, pH, temperature, and phosphate buffer concentration on the sensitivity of the biosensor was studied in detail. The biosensor exhibits fast response time (70s), good repeatability (3.2%, n=10) and storage stability (90% of initial sensitivity after 3-week storage). Common interferents including acetic acid, lactic acid, propionic acid, butyric acid, folic acid, methanol, glycine, DL-alpha-alanine and DL-cysteine do not cause significant interferences on the biosensor. The proposed biosensor method was successfully applied to determine the glucose content in real samples such as orange juice, red wine and tea drink and the results were comparable to that obtained from a spectrophotometric method. The glucose recovery test demonstrates that the proposed glucose biosensor offers an excellent, accurate and precise method for the determination of glucose in real samples.

Short-time effect of heavy metals upon microbial community activity.

Microcalorimetry was applied to assess and compare the toxic effect of heavy metals, such as As, Cu, Cd, Cr, Co, Pb and Zn, on the soil microbial activities and community. About 1.0 g soil spiked 5.0mg glucose and 5.0mg ammonium sulfate, the microbial activities were recorded as power-time curves, and their indices, microbial growth rate constant k, total heat evolution Q(T), metabolic enthalpy Delta H(met) and mass specific heat rate J(Q/S), were calculated. Comparing these thermodynamic parameters associated with growth yield, a general order of toxicity to the soil was found to be Cr>Pb>As>Co>Zn>Cd>Cu. When soil was exposed to heavy metals, the amount of bacteria and fungi decreased with the incubation time, and the bacterial number diminished sharply. It illustrates that fungi are more tolerant, and bacteria-fungi ratio would be altered under metal stress. To determine the status of the glucose consumed, a glucose biosensor with eggshell membrane was used to measure the remaining glucose in soil sample. Results showed that the time at which glucose was consumed completely was agreed with the microcalorimetric time to a large extent, and depended on the toxicity of heavy metals as well.

Biological and microcalorimetric studies of the toxic effect of organoarsenic(V) compounds to wild strain of Bacillus thuringiensis.

Microcalorimetric and biological methods were carried out to determine the toxicity of dimethylarsinic acid (DMA) and monomethylarsonic acid (MMA) to wild strain of Bacillus thuringiensis. Thermokinetic parameters were obtained from the power-time curves, showing that the peak-heat output power, total heat output, and number of colonies decreased with the increases in concentration of DMA and MMA. In addition, the generation time and peak maximal time increased with the increases in the dosage of DMA and MMA. The half inhibitory concentrations of DMA and MMA were 99.02 and 142.02 microg mL(-1), respectively for the wild strain of B. thuringiensis. DMA shows higher toxicity to bacteria than MMA. The toxicity resistance of B. thuringiensis against organoarsenic(V) is quite high for the wild strain. Our work demonstrates that microcalorimetry is a very sensitive, simple, and useful technique for in vitro investigation of the toxic effect of organoarsenic(V) on microbial activity.