Vol 5, No 2 (2020)

Table of Contents

Review

291 Views, 128 PDF Downloads
Ji-Dong Gu, Elizabeth Ka Wing Wu
DOI:10.26789/AEB.2020.02.003

Abstract

Petroleum-based plastics are an indispensable part of our daily life now because they are flexible, convenient, light weight, waterproof, and also have good mechanical strength and economical. They are especially suitable in products packaging, but they accumulate in soils, rivers and oceans, resulting in undesirable environmental and ecological hazards. Conventional plastics wastes in landfills occupy a much higher proportion of space because of their light-weight and extremely low biodegradation rate under anaerobic conditions. Composting is a treatment process to deal with biodegradable plastics (BPs) wastes and diverts a fraction of the wastes from landfilling to provide a feasible solution to the waste management problem. Biodegradability and degradation rate of plastics products depend on the fundamental chemical characteristics of the specific plastics mainly while environmental conditions and the establishment of an active degrading population of microorganisms contribute to a small extent of the fate of plastics after disposal. As the biodegradation rate varies among different plastics, a group of testing methods are available for assessing the degradability of different plastics and their products. Plasticizers in plastics and polymeric materials deserve a special attention up on their dispersal and ecological impact because of their endocrine-disrupting activity. The widely used phthalate esters are biodegradable by indigenous microorganisms in the environments, but the large quantity of them used is a serious issue to the environment and ecological health. However, there is an apparent cost difference between biodegradable and synthetic plastics, which hinder the commercialization of biodegradable ones for daily use. Separation of waste collection and education can contribute to the plastic waste management. It is unrealistic that biodegradable plastics are the solution to the problems facing today’s society on waste management. The ultimate goal is to reduce the use by society members so that amount of waste generated can be reduced so that waste products can be reduced from the sources.

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34-52

Commentary

925 Views, 302 PDF Downloads
Ji-Dong Gu
DOI:10.26789/AEB.2020.02.002

Abstract

Environmental biotechnology (EB) can play positive and an important role in detoxifying and eliminating pollutants, and cleaning up the contaminated sites of ecosystems, but the development of any EB is based largely on the scientific knowledge and results of (micro)biology and chemistry, and then application mainly on engineering and management. Biodegradation and bioremediation by definition are different in meaning and, as a result, they must be treated differently. On the fundamental basis, the biochemical reactions and the biochemical degradation pathway of any targeted toxicant concerned are basic information before the degradability of the selective pollutant by a microorganism can be claimed. Bioremediation becomes feasible for implementation with the knowledge of the biochemical reactions by the biological agent coupling with the engineering and management to achieve a successful attempt at a site. Though the degradability by a microorganism can be achieved in laboratory condition, the cleaning up of the pollutant at any site needs additional information and knowledge of the physical, chemical and ecological characteristics of the site to allow any success to be achieved. The broad EB can include utilization of pure and selective microorganisms, the biochemical reactions by either pure or mixed culture, enzymes, and metabolic products of microorganisms. In addition, microorganisms may also work in the form of biofilm to carry out the function to detoxify the toxic environmental chemicals. In addition to microorganisms, plants can play an important role in phytoremediation. Overall, environmental biotechnology needs at least three steps to prove its effectiveness from concept testing in laboratory, establishment of the mechanisms involved, workability in complex system and ecosystems, and lastly the implementation and practice on site. A laboratory success on degradation cannot be quickly and simply treated as a claim of EB for bioremediation for application.

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28-33

Research Articles

680 Views, 227 PDF Downloads
Xiao-Zhang Yu, Li Yang, Yu-Xi Feng
DOI:10.26789/AEB.2020.01.003

Abstract

Abiotic stress like drought and heavy metal imposes a negative impact on exposed plants’ growth and development, commences over production of reactive oxygen species (ROS) inside plant cells resulting in oxidative stress at the cellular level. After that, plants activate multiple defense mechanisms, within which the superoxide dismutase (SOD) family acts as the first line of defense to eliminate ROS. From the literature, it is evident that fewer studies have been carried out in combination with molecular evolution and phylogenetics, and expression profile of the SOD genes amidst dicot and the monocot at subcellular level against drought stress and cadmium (Cd) metal exposure. In the present study, SOD isogenes are identified in purposely elected two dicot plants i.e. Arabidopsis thaliana (9 genes), Solanum lycopersicum (8 genes) and two monocot plants namely Triticum aestivum (11 genes), and Oryza sativa (7 genes), respectively. Based on the amino acids sequence similarities, the identified proteins are classified into three subfamilies in accordance to their phylogenetic relationships, namely Cu/ZnSOD, FeSOD, and MnSOD. High variability observed between Cu/ZnSOD with other two groups i.e. FeSOD and MnSOD which showed lesser variation within them by using secondary structure predication. Subcellular localization suggested that genes encoding FeSOD, MnSOD and Cu/ZnSOD are predominant in chloroplasts, mitochondria, and cytoplasm, respectively in studied plants. The expression profiling through microarray analysis showed varied strategies of SOD isogenes against drought stress and Cd exposure individually. From the perspective of evolution, this study would expand our knowledge for vividly understanding the role of distinctive SOD isogenes in detoxifying ROS in different plants under various abiotic stresses.

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14-27
842 Views, 335 PDF Downloads
Yunjiang Yu, Liangzhong Li, Mingyang Li, Xiaohui Zhang, Zongrui Li, Xiaohui Zhu, Bigui Lin
DOI:10.26789/AEB.2020.01.002

Abstract

Xinfengjiang Reservoir (XFJR) is the largest drinking water source in the southern China, and plays a vital role in supporting the development of China's Pearl River delta. The levels, source Identification, potential ecological risks and health risk of eight metal elements including Zn, Pb, Ni, Mn, Cu, Cr, Cd and As in the sediments of the XFJR and Heyuan section of East River (HYER) were investigated. Sixteen sediment samples were collected from June to July 2016 in XFJR and HYER, and the concentrations of heavy metals (Zn, Pb, Ni, Mn, Cu, Cr, Cd) and As were analyzed simultaneously. Results showed that the contents of Zn, Pb, Ni, Mn, Cu, Cr, Cd and As in surface sediment of XFJR were 76.27, 36.63, 12.23, 293.61, 14.88, 60.38, 0.76 and 18.68 mg / kg , respectively, and were 76.47, 30.95, 24.47, 361.95, 23.80, 91.81, 0.68 and 7.31 mg / kg, respectively, for HYER. The pollution’s levels of the heavy metal and As was in the order of Cd > Zn > Cr > Mn > As > Cu > Ni > Pb. The spatial distribution pattern of heavy metal and As in the surface sediments of the studied area featured high concentrations in the northeastern region and low concentrations in the XFJR, with a gradual decrease along the river flow from north to south. The results of principal component analysis demonstrated that agricultural activities, industrial pollution and water vehicles were the main sources of heavy metals pollution. The potential ecological risk index of the region was 22.02, and the potential ecological risk of heavy metal and As were in the ordered of Ni > Cu > Pb > Cr > Zn > Mn > Cd >As, indicating slight ecological risk. In addition, the non-carcinogenic risk and carcinogenic risk of heavy metal and As in the surface sediment for adult and children were within acceptable level.

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Editorial

587 Views, 178 PDF Downloads
Ji-Dong Gu
DOI:10.26789/AEB.2020.02.001

Abstract

Identification and prediction of the current ongoing and future research trends are critically important to research scientists to be on track of the significantly important topics and also ahead of the others if all possible. Such information can be extrapolated by mining the existing data available from different databases to delineate the important research topics that many are working on and also the emerging ones that attract attention. Because of the readily availability of online published articles in Open Access mode and instant information in real time on viewing number, read and citations, a simple summary of the papers published in this journal over the past 4 years indicated clearly the most viewed research articles and topics are in line with the main stream information available, namely novel dehalogenase, thermophilic organisms and biotechnological application in bioleaching, souring inhibition in oil reservoirs, and the current public interest on plastics. This information can be used in refining one’s specific research to target for popularity and visibility.

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