Vol 4, No 2 (2019)

Table of Contents

Research Articles

290 Views, 178 PDF Downloads
Ying-Chun Huang, Na Wang, Bi-Yong Huang, Chun-Jiao Lu, Xiao-Zhang Yu
DOI:10.26789/AEB.2019.02.002

Abstract

The base excision repair (BER) pathway is an essential defense mechanism against oxidative damage of DNA in plants. Previous studies have reported that chromium (Cr) exposure causes oxidative stress and DNA damage due to accumulation of ROS. In this study, hydroponic experiments were carried out to investigate mRNA expression of 21 candidate genes involved in the BER pathway in rice seedlings exposed to Cr(III) using qRT-PCR. Changes of H2O2 and O2-• content in rice tissues and the relative growth rate (%) of rice seedlings were also determined. The results indicated that Cr(III) induced dose-dependent inhibition on the relative growth rate of rice seedlings. H2O2 content in roots were significantly increased. Changes of the content of H2O2 and O2-• in shoots was consistent. PCR analysis revealed that responses of selected 21 candidate genes to Cr(III) exposure were tissue specific. The BER pathway in roots was repressed by Cr(III) treatment but activated in shoots in response to Cr(III) exposure, suggesting that the BER pathway would play different roles in regulating and repairing DNA damage caused by Cr(III) exposure in rice.

 


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Biodegradation and Bioremediation

340 Views, 95 PDF Downloads
Dong-Sheng Li, Jun-Qiao Feng, Yi-Fan Liu, Lei Zhou, Jin-Feng Liu, Ji-Dong Gu, Bo-Zhong Mu, Shi-Zhong Yang
DOI:10.26789/AEB.2019.02.003

Abstract

Microorganisms with high oil-degrading ability are essential for bioremediation of oil-contaminated environments and oil spills. In the present study, a microbial consortium was enriched from a long-term oil-contaminated soil by acclimatization with crude oil, and was cultured with sucrose as a carbon source. Immobilization of the microbial consortium cells was prepared onto sodium alginate (SA) beads. To enhance the mass transfer of the immobilized microspheres, activated carbon, biochar, corn stalk and sawdust were used, respectively, to accelerate the degradation of petroleum hydrocarbons. The immobilized beads and the distribution of microbial cells inside the immobilized beads were examined using scanning electron microscopy (SEM). The degradation efficiency of total petroleum hydrocarbon (TPH) by different immobilized beads in aquatic systems (mineral salt medium, artificial seawater) was evaluated by gravimetric method after 7 d of incubation. Results showed that TPH degradation efficiency of the immobilized beads was higher than that of the microbial culture, and that of the immobilized beads containing adsorbent carriers was higher than the SA immobilized beads. The highest TPH degradation efficiencies of SA-CS immobilized beads in mineral salt and artificial seawater were up to 54.2% and 50.5%, respectively, and the highest TPH degradation efficiency of biostimulation + SA-AC immobilized beads treatment in oil-contaminated soil was up to 63.7% after 10 weeks of incubation. Our results suggest that the immobilized microorganism is a promising approach for a wide range of bioremediation applications in different petroleum-contaminated environments.


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336 Views, 84 PDF Downloads
Zomesh Artus Nath Maini, Niña Therese Bautista Flores, Enrico Praxides Muñoz
DOI:10.26789/AEB.2019.02.004

Abstract

Lead [Pb(II)] biosorption capacities of immobilized Talaromyces macrosporus on Moringa oleifera L. wood were compared against pure fungal and pure M. oleifera biomass. A Pb(II) contact test of 1000 ug/mL show similar Pb(II) removal of non-immobilized fungal biomass (F) and powdered wood colonized with fungi (WP+F), with WP+F producing more biomass. Powdered sorbents had higher Pb(II) uptake compared to whole sorbents analyzed through ICP-AES, possibly due to increased surface area for Pb(II) binding. FTIR analysis of the F, WP, and WP+F identified hydroxyl, amino, carbonyl, and sulfhydryl functional groups which constitute probable Pb(II)-affinitive binding sites. The biosorbents tested in a Continuous Flow Column (CF) adsorbed Pb(II) at 1000, 2000, and 4000 ug/mL in 30 minutes with the Pb(II) uptake of WP+F producing removal efficiencies at 91-95% regardless of initial Pb(II) concentration. WP+F also showed significantly higher q values than powdered wood (WP) at 42.67184.83 mg/g for the Pb(II) test concentrations. Recovery of Pb(II) from WP+F yielded 99.61% of adsorbed ions from 1000 ug/mL Pb(II), proving Pb(II) entrapment in the sorbent. This is the first study to describe biosorption capacities for T. macrosporus and M. oleifera softwood along with the wood’s viability as an immobilization scaffold. These results show the potential of using T. macrosporus immobilized on M. oleifera wood as a tool for removal of Pb(II) in wastewater with high Pb(II) concentrations.


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Biotechnology and Applications

236 Views, 105 PDF Downloads28 PDF Downloads
Rexiding Abuduaini, Naling Bai, Cai Hui, Sheng Wang, Hui Jiang, Yuhua Zhao
DOI:10.26789/AEB.2019.02.005

Abstract

Bioflocculants are commonly used in wastewater treatment. In this study, an efficient bioflocculant-producing strain, Bacillus sp. R1, was isolated and identified; strain R1 could efficiently produce bioflocculant BF-R1 with wheat bran hydrolysate. The characteristics and flocculation mechanisms of BF-R1 were determined and it was then applied for the granular carbon particles treatment in wastewater. Notably, 3.71 g of BF-R1 were produced when 200 mL/L wheat bran hydrolysate was used as the sole carbon and nitrogen source. BF-R1 contained polysaccharides, proteins, and glycoproteins and showed a good flocculating efficiency of 91.00% for granular carbon particles in contaminated wastewater when 3.50 g/L BF-R1 was added, thus achieving successful recycling of fine particle-contaminated wastewater. Taken together, our findings for the first time demonstrate that BF-R1 fermented using WBH can probably be a promising candidate agent for wastewater management processes.

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Commentary

255 Views, 118 PDF Downloads
Ji-Dong Gu
DOI:10.26789/AEB.2019.02.001

Abstract

Analytical chemistry allows an accurate quantification of the total concentrations of a range of chemicals in different media of the ecosystems and contaminated sites, but the numerical values do not have direct relevance to the toxicity of them because the measured concentrations do not represent the active fraction that imposes toxic effects on organisms. It is apparent that an assessment of pollutant concentrations in ecosystems shall be made with new innovation to obtain the organism exposed concentrations so that the subsequent toxicological effects based on these data can provide reliable estimate on toxicity for management decision accordingly. Applied Toxicology, e.g., Ecotoxicology, and Environmental Toxicology, therefore shall have a different scientific framework to adopt the use of a new concentration term for pollutants to establish a close relationship between the effective concentration in the ecosystem and the toxicity to the organisms to make a meaningful understanding of the ecotoxicology and environmental toxicity. In addition, the choice of the organisms as indicators for chemical toxicity assays is another critical issue and the organism shall be selected with an international consensus to establish a solid baseline for comparable results from different laboratories around the world. Doing this way, the Applied Toxicology can make great advancement and contributes to the society better on a more competitive level based on exact science similar to physical sciences today. A greater opportunity is ahead and effective action needs to be taken collectively and immediately to advance the new knowledge of this research subject.

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