Vol 2, No 1 (2017)

Table of Contents

RESEARCH ARTICLES

12 Views, 13 PDF Downloads
Xiong Zhi-Qiang, Wang Guo-Xing, Huo Zhao-Chen, Yan Lei, Gao Ya-Mei, Wang Yan-Jie, Gu Ji-Dong, Wang Wei-Dong
DOI:10.26789/AEB.2015.01.003

Abstract

Composting is a controlled biological process used to stabilize and transform waste into a soil treatment. Aeration rate is one factor that controls the process of composting, as it ensures the growth of adequate aerobic microbe populations. To investigate the effect of aeration rates on the physicochemical indexes of compost and the loss of nitrogen content during composting, aerobic composting processes with different aeration rates (A: 0.2 L min-1 kg-1 TS, B: 0.05 L min-1 kg-1 TS and C: 0 L min-1 kg-1 TS) were studied. Ammonium-nitrogen, nitrate nitrogen, total nitrogen and other factors in compost samples from different periods were measured. The results showed that aeration rate significantly affected O2 content under different conditions. The aeration rate also significantly affected water content, nitrate nitrogen, and nitrogen loss. NH3 emissions increased as aeration rates increased at high temperatures owing to nitrogen loss. These results showed that aeration rate had a significant effect on total nitrogen and ammonia emissions (p<0.05). Thus, optimization of the ventilation method could significantly increase seed germination rate. 


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12 Views, 2 PDF Downloads
Xiao-Zhang Yu, Fei-Fei Zhang
DOI:10.26789/AEB.2017.01.002

Abstract

Responses of phenolic compounds was hydroponically investigated in rice seedlings (Oryza sativa L. cv. XZX 45) treated with either Cr(III) or Cr(VI). Results indicated that rice seedlings are able to effectively sequester both species of Cr. Majority of Cr recovered in plant materials was accumulated in roots rather than shoots. Accumulation of total soluble phenolics, flavonoids and lignin in plant materials was quite evident due to Cr exposure, but displaying different responses between the two species of Cr. Distribution of total soluble phenolics and flavonoids was more at shoots, especially at younger segments of shoots, and less at roots, whereas the lignin content was detected more at the younger parts of shoots and less towards the root tips. It is suggestive from the current investigation that both Cr species caused production and accumulation of these secondary metabolites in rice seedlings. 

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19-24
14 Views, 6 PDF Downloads
Yongfeng Li
DOI:10.26789/AEB.2017.01.005

Abstract

Nanocellulose has many advantages, such as a wide range of sources of raw materials, renewability, biodegradability, high aspect ratio and large specific surface area. It can be potentially used in medicine, electronics, information technology, energy industry, aerospace and some other high-technological fields. For preparation of nanocellulose, it is particularly important to separate nanocellulose from raw materials by an environment-friendly method with environmental protection awareness. Consequently, we here report an effective and environmental friendly method to isolate nanocellulose from a shrub plant, i.e., Amorpha fruticosa Linn. Firstly, the plant fiber is pretreated with chemicals to remove lignin and hemicellulose; then the derived purified cellulose is pretreated with enzyme hydrolysis, followed by slight treatment of high-pressure homogenization. The results showed that with the assistance of enzyme pretreatment, effective isolation of nanocellulose could be achieved, resulting in materials with a uniform diameter distribution and an average value of about 10 nm. The aspect ratio of the derived nanocellulose is greater than 1000. Such results showed that the method was green and effective for nanocellulose isolation, and the derived biomaterial as a unique biocompatible and high-strength biomass nanomaterial could be used in biomedical, environmental protection and other fields. 


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34-38
54 Views, 16 PDF Downloads
Shuai Liu, Jiajie Hu, Jiaxian Shen, Shu Chen, Guangming Tian, Ping Zheng, Liping Lou, Fang Ma, Baolan Hu
DOI:10.26789/AEB.2017.01.004

Abstract

Ammonia oxidation is an important step of the nitrogen cycle and was considered to be conducted only by bacteria for a long time. The discovery of ammonia-oxidizing archaea (AOA) caused consideration of the relative contributions of these two functional groups in different niches and factors resulting in their niche segregation. Previous studies showed that many environmental factors may correlate to the abundance and distribution of AOA and AOB, including ammonia/ammonium concentration, pH, organic matters, oxygen concentration, temperature, salinity, sulfide concentration, phosphate concentration, soil moisture, and others. To understand the effects of environmental factors on AOA and AOB, five main environmental factors which may be related to each other were selectively reviewed independently. Here, we discuss the influences of ammonia concentration, pH, temperature, oxygen concentration and organic matters on the niche segregation of AOA and AOB, and try to explain ecology phenomena from physiological and genic level.

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Biodegradation and Bioremediation

9 Views, 2 PDF Downloads
Karen Choi Yuen Yip, Ji-Dong Gu
DOI:10.26789/aeb.2017.01.001

Abstract

Biodegradation of indole by the Pseudomonas putida strain mpky-1 isolated and purified from sediment of the Inner Deep Bay of Hong Kong was investigated. The starin had 99.1% similarity with P. putida known. The biochemical degradation pathway of indole involved a hydroxylation reaction at the C-2 position first to form oxindole followed by a second hydroxylation at the C-3 position to isatin prior to the cleavage of the 5-carbon ring. This bacterium grew better at 22oC though it was capable of growth at low temperature (15oC in this case) with a longer lag phase was too long. The bacterial specific growth rate increased from 0.0035 hr-1 to 0.0249 hr-1 and the biodegradation rate also increased from 15oC to 30oC. P. putida mpky-1 grew quicker at pH 6.4 (specific growth rate, 0.0115 hr-1) than pH 7.4 (specific growth rate, 0.0066 hr-1) and pH 8.4 (specific growth rate, 0.036 hr-1) although the lag time of bacterial growth at pH 7.4 and pH 8.4 (15.01 hr and 15.00 hr, respectively) was very similar. The decrease in bacterial growth rate was also observed when salinity increased from 0.5% to 3.0%. P. putida mpky-1 may adapt to the Mai Po and Inner Deep Bay and degrade indole due to the pollution.

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