scholarly journals Effect of nitrogen concentration on the growth rate and biochemical composition of the microalga, Isochrysis galbana

2020 ◽  
Vol 46 (2) ◽  
pp. 153-158 ◽  
Author(s):  
Mohammad Javad Zarrinmehr ◽  
Omidvar Farhadian ◽  
Fatemeh Paykan Heyrati ◽  
Javad Keramat ◽  
Eleni Koutra ◽  
...  
Biology ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 695
Author(s):  
Sara Farhadi ◽  
Behrooz Atashbar Kangarloei ◽  
Ahmad Imani ◽  
Kourosh Sarvi Moghanlou

B. orientalis, fairy shrimp, is often among the most conspicuous invertebrates inhabiting temporary aquatic habitats with a typical variation in environmental conditions. Its life history characteristics and biochemical composition were studied under four different photoperiodic regimes (24L:0D, 0L:24D, 16L:8D, and 12L:12D). The significantly highest cumulative and initial hatching rates (48 h) were obtained at 24L:0D (p < 0.05). Cultivating the larvae under different photoperiods did not significantly affect specific growth rate (SGR) (p > 0.05). However, higher final total body length and daily growth rate were recorded under constant darkness. Higher lipid content was found at 24L:0D to the extent that it was more than two times higher than that at 16L:8D and 12L:12D (p < 0.05). There was also a remarkable increase in body crude protein content at 24L:0D (p < 0.05). Body fatty-acid profiles of the fairy shrimps were also affected by culture condition (p < 0.05). Extension of lighting period resulted in a subtle increase in body contents of arginine, lysine, histidine, isoleucine, leucine, valine, methionine, and phenylalanine, especially in the group kept under a 16L:8D regime. The highest and lowest digestive enzyme activity was observed at 0L:24D and 24L:0D, respectively (p < 0.05). In contrast, the highest and lowest soluble protein content was recorded at 24L:0D and 0L:24D, respectively (p < 0.05). Similarly, antioxidant status was significantly higher at 0L:24D (p < 0.05). In conclusion, a 16L:8D light–dark cycle might be an optimal condition in terms of growth performance and physio-biochemical characteristics. These findings could be helpful in optimizing the rearing conditions for upscaling B. orientalis production.


1994 ◽  
Vol 41 (1) ◽  
pp. 23-27 ◽  
Author(s):  
E. Molina Grima ◽  
J. A. S�nchez P�rez ◽  
F. Garc�a Camacho ◽  
J. M. Fern�ndez Sevilla ◽  
F. G. Aci�n Fern�ndez

2021 ◽  
Author(s):  
Pfariso Maumela ◽  
Shaunita Rose ◽  
Eugene van Rensburg ◽  
Annie Chimphango ◽  
Johann Gorgens

Abstract Endoinulinases gene was expressed in recombinant Aspergillus niger for selective and high-level expression using an exponential fed-batch fermentation. The effects of the growth rate (µ), glucose feed concentration, nitrogen concentration and fungal morphology, on enzyme production were evaluated. A recombinant endoinulinases with a molecular weight of 66 KDa was secreted. Endoinulinases production was growth associated at µ> 0.04 h -1 , which is characteristic of the constitutive gpd promoter used for the enzyme production. The highest volumetric activity (670 U/ml) was achieved at a growth rate of 93% of µ max (0.07 h -1 ), while enzyme activity (506 U/ml) and biomass substrate yield (0.043 g biomassDW /g glucose ) significantly decreased at low µ (0.04 h -1 ). Increasing the feed concentration resulted in high biomass concentrations and viscosity, which necessitated high agitation for improved mixing and oxygen. However, the high agitation and low DO levels (ca. 8% of saturation) led to pellet disruption and growth in mycelial morphology. Enzyme production profiles, product (Y p/s ) and biomass (Y x/s ) yield coefficients were not affected by feed concentration and morphological change. The gradual increase in the concentration of nitrogen sources showed that, a nitrogen limited culture was not suitable for endoinulinases production in recombinant A. niger. Moreover, the increase in enzyme volumetric activity was still directly related to an increase in biomass concentration. An increase in nitrogen concentration, from 3.8 to 12 g/L, resulted in volumetric activity increase from 393 to 670 U/ml, but the Y p/s (10053 U/g glucose ) and Y x/s (0.049 g biomasDWs /g glucose ) did not significantly change. The data demonstrated the potential of recombinant A. niger and high cell density fermentation for the development of largescale endoinulinases production system.


1994 ◽  
Vol 41 (1) ◽  
pp. 23-27 ◽  
Author(s):  
E. Molina Grima ◽  
J. A. S�nchez P�rez ◽  
F. Garc�a Camacho ◽  
J. M. Fern�ndez Sevilla ◽  
F. G. Aci�n Fern�ndez

2011 ◽  
Vol 266 ◽  
pp. 89-92
Author(s):  
Shang Sheng Li ◽  
Ning Luo ◽  
Xiao Lei Li ◽  
Tai Chao Su ◽  
You Mou Zhou ◽  
...  

With adopting Al as the nitrogen getter in Ni70Mn25Co5 or Fe55Ni29Co16 catalyst, High-quality type-Ⅱa large diamonds have been grown under the conditions of about 5.5GPa and 1580K by using the temperature gradient method. While Al(2.0wt%) is added in the Fe55Ni29Co16, the nitrogen concentration(Nc) in the diamond is less than 1ppm. While Al(4.0wt%) is added in the Ni70Mn25Co5, the Nc in the diamond is highly arrived at 48ppm. The different of solubility of nitrogen in both catalyst at high pressure and high temperature is the basic reason of the different effect of eliminating nitrogen of Al. It can be shown in experamentals that Al is a less efficient nitrogen getter in Ni70Mn25Co5 than in Fe55Ni29Co16. While Al(2.0wt%) is added in the Fe55Ni29Co16, the high-quality type-Ⅱa large diamond, in which nitrogen is less than 1ppm and which the size was arrived at 3.3mm, had grown by decreasing the growth rate of diamond.


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