scholarly journals Identification of significant proxy variable for the physiological status affecting salt stress-induced lipid accumulation in Chlorella sorokiniana HS1

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Seung Hwan Oh ◽  
Yong Keun Chang ◽  
Jay Hyung Lee
Keyword(s):  
Lipid Accumulation ◽  
Chlorophyll Concentration ◽  
Estimation Method ◽  
Total Lipid Content ◽  
Multiple Linear Regression Model ◽  
Chlorella Sorokiniana ◽  
Physiological Status ◽  
Light Illumination ◽  
Proxy Variables ◽  
Lipid Induction

Abstract Background Current efforts on the optimization of the two-stage cultivation using stress-induced lipid accumulation have mostly focused only on the lipid induction stage. Although recent studies have shown that stress-induced lipid accumulation is affected by the physiological status of the cells harvested at the preceding cultivation stage, this issue has hardly been examined hitherto. Such a study needs to be carried out in a systematic way in order to induce lipid accumulation in a consistent and predictable manner with regard for variances seen at the cultivation stage. Results After a photoautotrophic cultivation of Chlorella sorokiniana HS1 in a modified BG11, harvested cells were re-suspended in the fresh medium, and then NaCl was added as the sole stress inducer with light illumination to induce additional accumulation of lipid. Effects of culture temperature on the lipid accumulation were analyzed by the Kruskal–Wallis test. From the microscopic observation, we had observed a definite increase in lipid body induced by the stress since the cell entered a stationary phase. A multiple linear regression model was developed so as to identify significant parameters to be included for the estimation of lipid induction. As a result, several key parameters at the end of cultivation, such as cell weight, total lipid content, chlorophyll a in a cell, and Fv/Fm, were identified as the important proxy variables for the cell’s physiological status, and the modeling accuracy was achieved by 87.6%. In particular, the variables related to Fv/Fm were shown to have the largest influence, accounting for 65.7% of the total variance, and the Fv/Fm had an optimal point of maximum induction at below its average. Clustering analysis using the K-means algorithm indicated that the algae which are 0.15 pg cell−1 or less in chlorophyll concentration, regardless of other conditions, had achieved high induction results. Conclusion Experimental results showed that it usually achieves high lipid induction after the cells naturally end their division and begin to synthesize lipid. The amount of lipid induction could be estimated by the selected proxy variables, and the estimation method can be adapted according to practical situations such as those with limited measurements.

Micro-pollutant Pb(II) mitigation and lipid induction in oleaginous microalgae Chlorella sorokiniana UUIND6

2021 ◽  
pp. 101613
Author(s):  
Manisha Nanda ◽  
Krishna Kumar Jaiswal ◽  
Vinod Kumar ◽  
Mikhail S. Vlaskin ◽  
Pankaj Gautam ◽  
...  
Keyword(s):  
Chlorella Sorokiniana ◽  
Oleaginous Microalgae ◽  
Lipid Induction

scholarly journals The Use of Urea and Kelp Waste Extract is A Promising Strategy for Maximizing the Biomass Productivity and Lipid Content in Chlorella sorokiniana

Plants ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 463 ◽  
Author(s):  
Ali Nawaz Kumbhar ◽  
Meilin He ◽  
Abdul Razzaque Rajper ◽  
Khalil Ahmed Memon ◽  
Muhammad Rizwan ◽  
...  
Keyword(s):  
Lipid Content ◽  
Fossil Fuels ◽  
Fossil Fuel ◽  
Lipid Production ◽  
Total Lipid Content ◽  
Biomass Productivity ◽  
Chlorella Sorokiniana ◽  
Biofuel Production ◽  
Promising Strategy ◽  
Waste Extract

The decline in fossil fuel reserves has forced researchers to seek out alternatives to fossil fuels. Microalgae are considered to be a promising feedstock for sustainable biofuel production. Previous studies have shown that urea is an important nitrogen source for cell growth and the lipid production of microalgae. The present study investigated the effect of different concentrations of urea combined with kelp waste extract on the biomass and lipid content of Chlorella sorokiniana. The results revealed that the highest cell density, 20.36 × 107 cells−1, and maximal dry biomass, 1.70 g/L, were achieved in the presence of 0.5 g/L of urea combined with 8% kelp waste extract. Similarly, the maximum chlorophyll a, b and beta carotenoid were 10.36 mg/L, 7.05, and 3.01 mg/L, respectively. The highest quantity of carbohydrate content, 290.51 µg/mL, was achieved in the presence of 0.2 g/L of urea and 8% kelp waste extract. The highest fluorescence intensity, 40.05 × 107 cells−1, and maximum total lipid content (30%) were achieved in the presence of 0.1 g/L of urea and 8% kelp waste extract. The current study suggests that the combination of urea and kelp waste extract is the best strategy to enhance the biomass and lipid content in Chlorella sorokiniana.

scholarly journals Experimental Study of Substrate Limitation and Light Acclimation in Cultures of the Microalgae Scenedesmus obliquus—Parameter Identification and Model Predictive Control

Processes ◽  
2020 ◽  
Vol 8 (12) ◽  
pp. 1551
Author(s):  
Federico Alberto Gorrini ◽  
Jesús Miguel Zamudio Lara ◽  
Silvina Inés Biagiola ◽  
José Luis Figueroa ◽  
Héctor Hernández Escoto ◽  
...  
Keyword(s):  
Model Predictive Control ◽  
Dynamic Model ◽  
Predictive Control ◽  
Initial Conditions ◽  
Incident Light ◽  
Chlorophyll Concentration ◽  
Scenedesmus Obliquus ◽  
Light Illumination ◽  
Bulk Substrate ◽  
Determination Of Parameters

In this study, the parameters of a dynamic model of cultures of the microalgae Scenedesmus obliquus are estimated from datasets collected in batch photobioreactors operated with various initial conditions and light illumination conditions. Measurements of biomass, nitrogen quota, bulk substrate concentration, as well as chlorophyll concentration are achieved, which allow the determination of parameters with satisfactory confidence intervals and model cross-validation against independent data. The dynamic model is then used as a predictor in a nonlinear model predictive control strategy where the dilution rate and the incident light intensity are simultaneously manipulated in order to optimize the cumulated algal biomass production.

scholarly journals Physiological Changes of Parachlorella Kessleri TY02 in Lipid Accumulation under Nitrogen Stress

2019 ◽  
Vol 16 (7) ◽  
pp. 1188 ◽  
Author(s):  
Yifan Gao ◽  
Jia Feng ◽  
Junping Lv ◽  
Qi Liu ◽  
Fangru Nan ◽  
...  
Keyword(s):  
Total Lipid ◽  
Total Protein ◽  
Lipid Accumulation ◽  
Lipid Synthesis ◽  
Total Lipid Content ◽  
Nitrogen Stress ◽  
Total Protein Content ◽  
Total Carbohydrate ◽  
Chlorophyll Fluorescence Parameters ◽  
Parachlorella Kessleri

In order to study the effects of nitrogen stress on the lipid synthesis of Parachlorella kessleri TY02 and to understand the changes in growth, photosynthetic pigments, total protein and total carbohydrate contents during lipid accumulation, the cells of the strain were cultured in nitrogen-deficient (N−) and nitrogen-rich (N+) media for one week. Changes in cell growth, chlorophyll content, chlorophyll fluorescence parameters, neutral lipid and total lipid content, total protein content and total carbohydrate content were measured and analyzed. The results showed that, under nitrogen stress, the algal strain grew slowly, and chlorophyll and total protein contents decreased, while total carbohydrate and total lipid contents increased. This indicated that, under nitrogen stress, most of the carbon flowed to the synthesis of lipids and carbohydrates. Meanwhile, reducing the nitrogen content was a relatively economical and easy to operate method of promoting lipid accumulation.

Quantification of Concrete Waste Generated in Housing Construction Sites via Site Sampling: Development of a Multiple Linear Regression Model

2015 ◽  
Vol 802 ◽  
pp. 676-681
Author(s):  
Siti Hafizan Hassan ◽  
Hamidi Abdul Aziz ◽  
Izwan Johari ◽  
Mohd Nordin Adlan
Keyword(s):  
Linear Regression ◽  
Regression Model ◽  
Multiple Linear Regression ◽  
Linear Regression Analysis ◽  
Estimation Method ◽  
Multiple Linear Regression Model ◽  
Real Data ◽  
Housing Construction ◽  
Construction Sites ◽  
Average Percentage

Waste generated in construction sites has recently increased and has become an uncontrollable cause of environmental problems and profit loss to contractors. The lack of real data or research on such wastes is due to the lack of suitable policies regarding this issue. The actions of contractors are not controlled by rules on this issue. This situation leads to the lack of action or awareness on the side of the contractor. Concrete waste is also part of the waste generated in construction sites. We determine the concrete waste generated in construction stages and conduct multiple linear regression analysis of the amount of column waste generated. The methodology employed in this study involves site observations, interviews with site personnel, and sampling at housing construction sites. The estimation method is utilized for the sampling of concrete waste. Results show that the average percentage of column waste is 13.93% and that of slab waste is 0.34%. These percentage values are derived from the total order of the concrete. The difference is due to the sizes of structures and method of handling. The regression model obtained from the sample data on column waste resulted in an adjustedR2value of 0.895. Therefore, the model predicts approximately 89.5% of the factors involved in concrete waste generation.

scholarly journals A Mathematical Model of Neutral Lipid Content in terms of Initial Nitrogen Concentration and Validation in Coelastrum sp. HA-1 and Application in Chlorella sorokiniana

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Zhenhua Yang ◽  
Yue Zhao ◽  
Zhiyong Liu ◽  
Chenfeng Liu ◽  
Zhipeng Hu ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Lipid Content ◽  
Lipid Accumulation ◽  
Nitrogen Concentration ◽  
Lipid Production ◽  
Lipid Synthesis ◽  
Quantitative Relationship ◽  
Chlorella Sorokiniana ◽  
High Lipid ◽  
Nitrogen Concentrations

Microalgae are considered to be a potential major biomass feedstock for biofuel due to their high lipid content. However, no correlation equations as a function of initial nitrogen concentration for lipid accumulation have been developed for simplicity to predict lipid production and optimize the lipid production process. In this study, a lipid accumulation model was developed with simple parameters based on the assumption protein synthesis shift to lipid synthesis by a linear function of nitrogen quota. The model predictions fitted well for the growth, lipid content, and nitrogen consumption of Coelastrum sp. HA-1 under various initial nitrogen concentrations. Then the model was applied successfully in Chlorella sorokiniana to predict the lipid content with different light intensities. The quantitative relationship between initial nitrogen concentrations and the final lipid content with sensitivity analysis of the model were also discussed. Based on the model results, the conversion efficiency from protein synthesis to lipid synthesis is higher and higher in microalgae metabolism process as nitrogen decreases; however, the carbohydrate composition content remains basically unchanged neither in HA-1 nor in C. sorokiniana.

Reflectance indices as nondestructive indicators of the physiological status of Ceratonia siliqua seedlings under varying moisture and temperature regimes

2012 ◽  
Vol 39 (7) ◽  
pp. 588 ◽  
Author(s):  
Júlio Osório ◽  
Maria Leonor Osório ◽  
Anabela Romano
Keyword(s):  
Water Availability ◽  
Spectral Reflectance ◽  
Water Status ◽  
Chlorophyll Concentration ◽  
Photochemical Efficiency ◽  
Principal Component ◽  
Physiological Status ◽  
Total Chlorophyll ◽  
Ceratonia Siliqua ◽  
Reflectance Indices

We investigated the use of spectral reflectance techniques to monitor the physiological responses of Ceratonia siliqua L. seedlings exposed to different levels of water availability under normal (25 : 18°C, day : night) and elevated (32 : 21°C, day : night) temperatures. Three spectral reflectance indices (photochemical reflectance index, PRI; water index, WI; red edge position, REP) were measured along with water status, chlorophyll fluorescence and chlorophyll concentration variables in the leaves of well watered, moderately stressed, severely stressed and rehydrated plants under each temperature regime. The PSII effective photochemical efficiency (φ2) and the intrinsic efficiency of open PSII centres (F′v/F′m) correlated significantly with PRI, and these three variables loaded heavily onto the same principal component of a three-factor principal component analysis solution. Water concentration (WC) and the succulence index (SI) were more strongly correlated with WI than either water potential (ΨPD) or relative water content (RWC). Accordingly, WI, WC and SI were combined in the second principal component, and ΨPD and RWC in the third. Our results provide clear evidence for interaction between water availability and temperature in the WI and the PRI response segments of the reflectance curves. Elevated temperature inhibited the recovery of WI spectral segments more than that of the PRI segments in SS plants. REP showed a strongly positive linear relationship with leaf total chlorophyll concentration across all water and temperature treatment combinations. PRI, WI and REP are therefore reliable markers that can be used to monitor φ2, WC and total chlorophyll concentration, respectively, in C. siliqua seedlings under drought and temperature stress.

scholarly journals Real Estate Credit and Liquidity Risk with Ownership Structure as Moderating Variables in Banking Companies Listed on The Indonesia Stock Exchange

2021 ◽  
Vol 14 (2) ◽  
pp. 166
Author(s):  
Muhammad Madyan ◽  
Ilham Ramadhani ◽  
Rayindha Galuh Setyowati
Keyword(s):  
Real Estate ◽  
Stock Exchange ◽  
Estimation Method ◽  
Liquidity Risk ◽  
Multiple Linear Regression Model ◽  
Foreign Ownership ◽  
Least Square ◽  
Government Ownership ◽  
Role Of Government ◽  
Positive Effect

The purpose of this study is to investigate the effect of real estate credit on liquidity risk. This study also looked at the role of government ownership and foreign ownership in moderating the effect of real estate credit on bank liquidity risk. There are 43 banking companies listed on the Indonesia Stock Exchange for the 2014-2018 period used as samples. This study used a multiple linear regression model with the Ordinary Least Square (OLS) estimation method and robustness tests using the Maximum Likelihood (MLE) estimation method. The results of this study concluded that real estate credit has a significant positive effect on liquidity risk. Government ownership strengthens the positive effect of real estate credit on liquidity risk, while foreign ownership weakens the positive effect of real estate credit on liquidity risk.

scholarly journals Application of RNA subcellular fraction estimation method to explore RNA localization regulation

2021 ◽  
Author(s):  
Xiaomin Dai ◽  
Yangmengjie Li ◽  
Weizhen Liu ◽  
Xiuqi Pan ◽  
Chenyue Guo ◽  
...  
Keyword(s):  
Subcellular Fraction ◽  
Estimation Method ◽  
Multiple Linear Regression Model ◽  
Subcellular Fractionation ◽  
Rna Localization ◽  
Global Scale ◽  
Cellular Compartment ◽  
Localization Pattern ◽  
Relative Localization ◽  
The Difference

Abstract RNA localization is involved in multiple biological processes. Recent advances in subcellular fractionation-based sequencing approaches uncovered localization pattern on a global scale. Most of existing methods adopt relative localization ratios (such as ratios of separately normalized transcripts per millions of different subcellular fractions without considering the difference in total RNA abundances in different fractions), however, absolute ratios may yield different results on the preference to different cellular compartment. Experimentally, adding external Spike-in RNAs to different fractionation can be used to obtain absolute ratios. In addition, a spike-in independent computational approach based on multiple linear regression model can also be used. However, currently, no custom tool is available. To solve this problem, we developed a method called subcellular fraction abundance estimator to correctly estimate relative RNA abundances of different subcellular fractionations. The ratios estimated by our method were consistent with existing reports. By applying the estimated ratios for different fractions, we explored the RNA localization pattern in cell lines and also predicted RBP motifs that were associated with different localization patterns. In addition, we showed that different isoforms of same genes could exhibit distinct localization patterns. To conclude, we believed our tool will facilitate future subcellular fractionation-related sequencing study to explore the function of RNA localization in various biological problems.

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