scholarly journals Chemical and Physical Culture Conditions Significantly Influence the Cell Mass and Docosahexaenoic Acid Content of Aurantiochytrium limacinum Strain PKU#SW8

Marine Drugs ◽  
2021 ◽  
Vol 19 (12) ◽  
pp. 671
Author(s):  
Xiaohong Chen ◽  
Biswarup Sen ◽  
Sai Zhang ◽  
Mohan Bai ◽  
Yaodong He ◽  
...  
Keyword(s):  
Docosahexaenoic Acid ◽  
Large Scale ◽  
Cell Mass ◽  
River Estuary ◽  
Nitrogen Sources ◽  
Pearl River Estuary ◽  
Culture Conditions ◽  
Physical Culture ◽  
Seawater Ph ◽  
Dha Production

Thraustochytrids are well-known unicellular heterotrophic marine protists because of their promising ability to accumulate docosahexaenoic acid (DHA). However, the implications of their unique genomic and metabolic features on DHA production remain poorly understood. Here, the effects of chemical and physical culture conditions on the cell mass and DHA production were investigated for a unique thraustochytrid strain, PKU#SW8, isolated from the seawater of Pearl River Estuary. All the tested fermentation parameters showed a significant influence on the cell mass and concentration and yield of DHA. The addition of monosaccharides (fructose, mannose, glucose, or galactose) or glycerol to the culture medium yielded much higher cell mass and DHA concentrations than that of disaccharides and starch. Similarly, organic nitrogen sources (peptone, yeast extract, tryptone, and sodium glutamate) proved to be beneficial in achieving a higher cell mass and DHA concentration. PKU#SW8 was found to grow and accumulate a considerable amount of DHA over wide ranges of KH2PO4 (0.125–1.0 g/L), salinity (0–140% seawater), pH (3–9), temperature (16–36 °C), and agitation (140–230 rpm). With the optimal culture conditions (glycerol, 20 g/L; peptone, 2.5 g/L; 80% seawater; pH 4.0; 28 °C; and 200 rpm) determined based on the shake-flask experiments, the cell mass and concentration and yield of DHA were improved up to 7.5 ± 0.05 g/L, 2.14 ± 0.03 g/L, and 282.9 ± 3.0 mg/g, respectively, on a 5-L scale fermentation. This study provides valuable information about the fermentation conditions of the PKU#SW8 strain and its unique physiological features, which could be beneficial for strain development and large-scale DHA production.

Morphodynamic Process of Dachan Bay in Pearl River Estuary Affected by Human Activities

2014 ◽  
Vol 638-640 ◽  
pp. 1257-1260
Author(s):  
Rong Yao Ji ◽  
Qun Xu ◽  
Si Ping Mo
Keyword(s):  
Tidal Flat ◽  
Human Activities ◽  
Large Scale ◽  
Morphological Changes ◽  
River Estuary ◽  
Pearl River Estuary ◽  
Pearl River ◽  
Landsat Images ◽  
Change Analysis ◽  
Factors Affecting

The surrounding area of the Dachan Bay in the Pearl River Estuary has one of the highest economic development rates of China. Rapid industrialization and urbanization has resulted in extensive changes in land use, including the tidal flat reclamation and harbor construction. For the analysis of the morphological changes of the Dachan Bay, multi-temporal Landsat images have been digitized by using the integrated RS and GIS technique, and the digital elevation modes in different years were set up in combination with topographical and nautical data. From the change analysis, it can be concluded that the sea area of the Dachan Bay decreases to 6.0 km2, by 87.6% between 1907a and 2011a due to the large-scale tidal flat reclamation, and the maximum downcutting depth of the seabed in the entrance area is over 10m mainly caused by extensive harbor construction. Based on the research of the morphological change in recent decades, it is suggested that the human activities have become one of the major factors affecting the morphological processes of the Dachan Bay.

Study on the Characteristics of Temporal and Spatial Variation of Suspended Sediment in the Pearl River Estuary

2009 ◽  
Author(s):  
Wei Zhang ◽  
Mingyuan Yang ◽  
Xiaolin Zhang ◽  
Peipei Dong
Keyword(s):  
Spatial Variation ◽  
Suspended Sediment ◽  
Large Scale ◽  
Research Result ◽  
River Estuary ◽  
Pearl River Estuary ◽  
Tidal Range ◽  
Pearl River ◽  
Temporal And Spatial Variation ◽  
Temporal And Spatial

The Lingding Estuary is one of the main parts of the whole Pearl River Delta, which lies in the South Sea, China. It is about 60 km wide from Hong Kong in the east to Macao in the west and the water areas are approximately 2110 km2. The process of suspended sediment movement is influenced by many factors, such as the estuarine geometry, tidal range and ravine flows etc.. In this paper, large scale hydrological observations in the Lingding Estuary have been respectively carried out in July, 2003. Based on these data, characteristics of temporal and spatial variation of suspended sediment concentration (SSC) in the Lingding Estuary are studied. The research result shows that SSC changes with the variation of tide current and runoff, the sediment re-suspension is often occurred 1–2 hour following the flood or ebb tide. The maximum turbidity appears near the gauging station V3. In the flood dominant stage, the sediments move towards the mainland, while during the ebb sediments move down.

scholarly journals Large-scale Long Time-series InSAR Land Subsidence Research in the Pearl River Estuary

2020 ◽  
Author(s):  
xiaowen luo ◽  
Hui Gao ◽  
Ziyin Wu ◽  
Shoujun Li ◽  
Jihong Shang ◽  
...  
Keyword(s):  
Time Series ◽  
Land Subsidence ◽  
Large Scale ◽  
Human Life ◽  
River Estuary ◽  
Pearl River Estuary ◽  
Pearl River ◽  
Temporal And Spatial Distribution ◽  
The Pearl River Estuary ◽  
The Pearl River

Abstract Due to the influence of human activity and changes in natural conditions, the Pearl River Estuary (PRE) has emerged as a large-scale area of land subsidence, which represents a serious threat to the quality of human life and sustainable socio-economic development. In response to the problems associated with the lack of man-made targets of traditional time-series Interferometric Synthetic Aperture Radar (InSAR) in estuaries and other coastal areas, a distributed scatterers (DS) InSAR method based on a spatially adaptive filter and an eigendecomposition algorithm to estimating the optimal phase of statistically homogeneous DS was applied to obtain subsidence data using 67 scenes Sentinel-1A SAR images covering the PRE. The temporal and spatial distribution characteristics of land subsidence were analyzed. The results suggest that land subsidence in the PRE was widespread and unevenly distributed with large differences between 2015 and 2018. The northwest and southeast are the main subsidence areas, with a maximum sedimentation rate greater than 25 mm/year.

scholarly journals Culturable Diversity and Lipid Production Profile of Labyrinthulomycete Protists Isolated from Coastal Mangrove Habitats of China

Marine Drugs ◽  
2019 ◽  
Vol 17 (5) ◽  
pp. 268 ◽  
Author(s):  
Qiuzhen Wang ◽  
Huike Ye ◽  
Yunxuan Xie ◽  
Yaodong He ◽  
Biswarup Sen ◽  
...  
Keyword(s):  
Rotation Rate ◽  
Lipid Accumulation ◽  
Large Scale ◽  
Saturated Fatty Acids ◽  
Lipid Production ◽  
Culture Conditions ◽  
Cell Biomass ◽  
Initial Ph ◽  
Dha Production

Labyrinthulomycete protists have gained significant attention in the recent past for their biotechnological importance. Yet, their lipid profiles are poorly described because only a few large-scale isolation attempts have been made so far. Here, we isolated more than 200 strains from mangrove habitats of China and characterized the molecular phylogeny and lipid accumulation potential of 71 strains. These strains were the closest relatives of six genera namely Aurantiochytrium, Botryochytrium, Parietichytrium, Schizochytrium, Thraustochytrium, and Labyrinthula. Docosahexaenoic acid (DHA) production of the top 15 strains ranged from 0.23 g/L to 1.14 g/L. Two labyrinthulid strains, GXBH-107 and GXBH-215, exhibited unprecedented high DHA production potential with content >10% of biomass. Among all strains, ZJWZ-7, identified as an Aurantiochytrium strain, exhibited the highest DHA production. Further optimization of culture conditions for strain ZJWZ-7 showed improved lipid production (1.66 g/L DHA and 1.68 g/L saturated fatty acids (SFAs)) with glycerol-malic-acid, peptone-yeast-extract, initial pH 7, 28 °C, and rotation rate 150 rpm. Besides, nitrogen source, initial pH, temperature, and rotation rate had significant effects on the cell biomass, DHA, and SFAs production. This study provides the identification and characterization of nearly six dozen thraustochytrids and labyrinthulids with high potential for lipid accumulation.

Acute toxicity ofCochlodinium geminatumbloom waters from Pearl River Estuary on larvae of brine shrimp,fish and shrimp

2013 ◽  
Vol 37 (9) ◽  
pp. 1328
Author(s):  
Ni WU ◽  
Tao JIANG ◽  
Tianjiu JIANG ◽  
Songhui LV ◽  
Qingliu HUAN
Keyword(s):  
Acute Toxicity ◽  
Brine Shrimp ◽  
River Estuary ◽  
Pearl River Estuary ◽  
Pearl River

A Real-Time Mathematical Model for Three-Dimensional Tidal Flow and Water Quality

1991 ◽  
Vol 24 (6) ◽  
pp. 171-177 ◽  
Author(s):  
Zeng Fantang ◽  
Xu Zhencheng ◽  
Chen Xiancheng
Keyword(s):  
Mathematical Model ◽  
Water Quality ◽  
Real Time ◽  
Control Volume ◽  
Tidal Flow ◽  
Three Dimensional ◽  
River Estuary ◽  
Pearl River Estuary ◽  
Practical Application ◽  
The Pearl River

A real-time mathematical model for three-dimensional tidal flow and water quality is presented in this paper. A control-volume-based difference method and a “power interpolation distribution” advocated by Patankar (1984) have been employed, and a concept of “separating the top-layer water” has been developed to solve the movable boundary problem. The model is unconditionally stable and convergent. Practical application of the model is illustrated by an example for the Pearl River Estuary.

Evaluation of the growth and sporulation of different entomopathogenic fungi in different liquid and solid media at varied concentrations

2017 ◽  
Vol 6 (8) ◽  
pp. 5459
Author(s):  
Chandra Teja K. ◽  
Rahman S. J.
Keyword(s):  
Entomopathogenic Fungi ◽  
Large Scale ◽  
Insect Pests ◽  
Culture Media ◽  
Virulent Strain ◽  
Carbon Sources ◽  
Nitrogen Sources ◽  
Maximum Growth ◽  
Nutritional Requirements ◽  
Virulent Strains

Entomopathogenic fungi like Beauveria bassiana, Metarhizium anisopliae and Lecanicillium lecanii are used in biological control of agricultural insect pests. Their specific mode of action makes them an effective alternative to the chemical Insecticides. Virulent strains of Entomopathogenic fungi are effectively formulated and used as bio-insecticides world-wide. Amenable and economical multiplication of a virulent strain in a large scale is important for them to be useful in the field. Culture media plays a major role in the large-scale multiplication of virulent strains of Entomopathogens. Different substrates and media components are being used for this purpose. Yet, each strain differs in its nutritional requirements for the maximum growth and hence it is necessary to standardize the right components and their optimum concentrations in the culture media for a given strain of Entomopathogen. In the current study, three different nitrogen sources and two different carbon sources were tried to standardize the mass multiplication media for seven test isolates of Entomopathogenic fungi. A study was also conducted to determine the ideal grain media for the optimum conidial yields of the test isolates. Yeast extract was found to be the best Nitrogen source for the isolates. The isolates tested, differed in their nutritional requirements and showed variation in the best nitrogen and carbon sources necessary for their growth. Variation was also found in the optimum concentration of both the ingredients for the growth and sporulation of the isolates. In the solid-state fermentation study, rice was found to be the best grain for the growth of most of the fungi followed by barley. The significance of such a study in the development of an effective Myco-insecticide is vital and can be successfully employed in agriculture is discussed.

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