scholarly journals Investigation of the Relationship between Bacteria Growth and Lipid Production Cultivating of Microalgae Chlorella Vulgaris in Seafood Wastewater

Energies ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 2282 ◽  
Author(s):  
Thi Dong Phuong Nguyen ◽  
Duc Huy Nguyen ◽  
Jun Wei Lim ◽  
Chih-Kai Chang ◽  
Hui Yi Leong ◽  
...  
Keyword(s):  
Chlorella Vulgaris ◽  
Lipid Content ◽  
Lipid Accumulation ◽  
Lipid Production ◽  
Oxygen Demand ◽  
Value Added ◽  
Bacteria Growth ◽  
Microalgae Culture ◽  
The Relationship ◽  
Microalgae Growth

Algae biorefinery is gaining much attention for the sustainable production of value-added products (e.g., biofuels, protein supplements etc.) globally. The current study aimed to investigate the relationship between lipid production and bacteria growth by an initial microalgae Chlorella vulgaris density culture in seafood wastewater effluent (SWE). According to our results, the initial C. vulgaris concentration in SWE influenced lipid accumulation. The concentration ranged from 25–35 mg·L−1 which corresponds to SWE’s chemical oxygen demand concentration of 365.67 ± 3.45 mg·L−1. A higher microalgae growth rate and lipid content of 32.15 ± 1.45% was successfully attained. A higher lipid content, approximately double, was observed when compared to the control (16.8 ± 0.5%). Moreover, this study demonstrates that bacteria inhibited microalgae growth as the initial cell density stepped over 35 mg·L−1, which also affected lipid accumulation. This study shows an optimal lipid accumulation attained at moderate Chlorella vulgaris density culture in SWE. Hence, wastewater treatment incorporating microalgae culture could be greatly developed in the future to achieve a greener environment.

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.

scholarly journals Marine microalgae co-cultured with floc-forming bacterium: Insight into growth and lipid productivity

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11217
Author(s):  
Chin Sze Yee ◽  
Victor Tosin Okomoda ◽  
Fakriah Hashim ◽  
Khor Waiho ◽  
Siti Rozaimah Sheikh Abdullah ◽  
...  
Keyword(s):  
Cell Density ◽  
Chlorella Vulgaris ◽  
Lipid Content ◽  
Lipid Accumulation ◽  
Axenic Culture ◽  
Cell Number ◽  
The Other ◽  
Biomass Growth ◽  
Microalgae Biomass ◽  
Insight Into

This study investigated the effect of co-culturing microalgae with a floc-forming bacterium. Of the six microalgae isolated from a biofloc sample, only Thalassiosira weissflogii, Chlamydomonas sp. and Chlorella vulgaris were propagated successfully in Conway medium. Hence, these species were selected for the experiment comparing microalgae axenic culture and co-culture with the floc-forming bacterium, Bacillus infantis. Results obtained showed that the co-culture had higher microalgae biomass compared to the axenic culture. A similar trend was also observed concerning the lipid content of the microalgae-bacterium co-cultures. The cell number of B. infantis co-cultured with T. weissflogii increased during the exponential stage until the sixth day, but the other microalgae species experienced a significant early reduction in cell density of the bacteria at the exponential stage. This study represents the first attempt at co-culturing microalgae with B. infantis, a floc-forming bacterium, and observed increased biomass growth and lipid accumulation compared to the axenic culture.

scholarly journals Pretreatments for enhancing sewage sludge reduction and reuse in lipid production

2020 ◽  
Author(s):  
Jiaxin Chen ◽  
Ji Li ◽  
Xiaolei Zhang ◽  
Zhaoyang Wu
Keyword(s):  
Lipid Content ◽  
Solid Phase ◽  
Lipid Production ◽  
Oxygen Demand ◽  
Rhodotorula Glutinis ◽  
Wastewater Sludge ◽  
Sludge Reduction ◽  
Acid Pretreatment ◽  
Sludge Management ◽  
Biological Sludge

Abstract Background: Converting wastewater sludge to lipid is considered as one of the best strategies of sludge management. The current problem of lipid production from wastewater sludge is the low yield (0.10-0.16 g lipid/g dry sludge) due to the low availability of easily uptaken materials (such as soluble monosaccharide and oligosaccharide) in sludge to oleaginous microorganism (Rhodotorula glutinis, Trichosporon oleaginosus, Lipomyces starkeyi). Pretreatments are efficient methods to improve sludge bioavailability. This study is aimed to achieve high lipid production from sludge and high sludge reduction. Results: In this study, it was observed that the soluble chemical oxygen demand (SCOD) had significantly increased after different pretreatment. The SCOD in the supernatant was increased from 32.64 to 180.25 mg/L, 924.16 mg/L, 1029.89mg/L and 3708.31 mg/L after acidic (pH 2 for 2 h), alkaline (pH 12 for 2 h), microwave irradiation (15 min with 5 min interval), and ultrasonication (30 min at 450 W and 20 kHz frequency with 5 s on and 2 s off mode) pretreatment, respectively. Pretreatments have also increased the release of total nitrogen (TN) and total phosphorus (TP) from solids. The sludge after different pretreatments were used as medium for lipid production, and the highest lipid content (36.67% g/g) was obtained in the fermentation with ultrasonication pretreatment sludge, and the sludge reduction was 63.10%. For other pretreatments, the lipid content and sludge reduction were 18.42% and 32.63% in acid pretreatment case, 21.08% and 36.44% in alkaline pretreatment case, and 26.31% and 43.03% in microwave pretreatment case, respectively.Conclusion: It was found that ultrasonication pretreatment was the most efficient way to increase the sludge biodegradability (SCOD) and to release TN and TP from solid phase to liquid phase. Pretreated sludge for lipid production achieved significant improvement in lipid yield and sludge reduction. Lipids produced from pretreated sludge were transesterified to biodiesel and the analysis showed that the biodiesel had a similar composition as commercial biodiesel. The study reveals that pretreatment on sludge is a promising method for enhancing biological sludge management efficiency.

scholarly journals Fast media optimization for mixotrophic cultivation of Chlorella vulgaris

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Valerie C. A. Ward ◽  
Lars Rehmann
Keyword(s):  
Cell Density ◽  
Lipid Content ◽  
Lipid Accumulation ◽  
Accumulation Rate ◽  
Lipid Production ◽  
Total Lipid Content ◽  
Mixotrophic Cultivation ◽  
Cell Weight ◽  
Dry Cell Weight ◽  
Dry Cell

AbstractMicroalgae can accumulate large proportions of their dry cell weight as storage lipids when grown under appropriate nutrient limiting conditions. While a high ratio of carbon to nitrogen is often cited as the primary mode of triggering lipid accumulation in microalgae, fast optimization strategies to increase lipid production for mixotrophic cultivation have been difficult to developed due to the low cell densities of algal cultures, and consequently the limited amount of biomass available for compositional analysis. Response surface methodologies provide a power tool for assessing complex relationships such as the interaction between the carbon source and nitrogen source. A 15 run Box-Behnken design performed in shaker flasks was effective in studying the effect of carbon, nitrogen, and magnesium on the growth rate, maximum cell density, lipid accumulation rate, and glucose consumption rate. Using end-point dry cell weight and total lipid content as assessed by direct transesterification to FAME, numerical optimization resulted in a significant increase in lipid content from 18.5 ± 0.76% to 37.6 ± 0.12% and a cell density of 5.3 ± 0.1 g/L to 6.1 ± 0.1 g/L between the centre point of the design and the optimized culture conditions. The presented optimization process required less than 2 weeks to complete, was simple, and resulted in an overall lipid productivity of 383 mg/L·d.

Integrated Dairy Plant Effluent Treatment and Production of Biomass and Lipids using Micro Algae - "Chlorella vulgaris"

2012 ◽  
Vol 10 (1) ◽  
Author(s):  
Bharathiraja Balasubramaniyan ◽  
Jayamuthunagai Jayaraman
Keyword(s):  
Chlorella Vulgaris ◽  
Lipid Content ◽  
Research Work ◽  
Algal Species ◽  
Oxygen Demand ◽  
Effluent Treatment ◽  
Toxic Substances ◽  
Pure Strain ◽  
Treated Effluent ◽  
High Lipid

Abstract Algal biomass is a potentially inexpensive source of energy which has high lipid content. As India is the Asia’s largest milk producing country (104.8 million tons in the year 2008), the milk production terminates with an effluent production of 5.24% of the total milk produced i.e., 20 million tons of dairy waste is produced. This effluent can be broken down in many ways, but a more economical way is broken down by the growth of the algal species Chlorella vulgaris which results in the tremendous reduction in various toxic salts concentration and other complex chemicals. As the dairy effluent is hostile to the natural environment, the algae is used not only to break down the toxic substances but also to produce Biomass, which is produced at a rate of 17g/l, which contains a lipid content of 30% ( from 1:1 ratio of effluent and water). Also the treated effluent has low chemical oxygen demand [COD], hence this can be used for irrigation of farms mainly those which are heavily fed with chemical fertilizers. The biosynthesis of organics salts, alkanoates [PHAs] and other phenolic compounds, involves algal species the process is secured by using i) large inoculums ii) tolerant strain (pure strain or GM, if available). This research work uses the pure strain of Chlorella vulgaris which involves the treatment of effluent with three different dilutions and analyzing them.

scholarly journals Molecular Mechanism of Lipid Accumulation and Metabolism of Oleaginous Chlorococcum sphacosum GD from Soil under Salt Stress

2021 ◽  
Vol 22 (3) ◽  
pp. 1304
Author(s):  
Hang Su ◽  
Jia Feng ◽  
Junping Lv ◽  
Qi Liu ◽  
Fangru Nan ◽  
...  
Keyword(s):  
Salt Stress ◽  
Fatty Acid ◽  
Lipid Content ◽  
Salt Concentration ◽  
Lipid Accumulation ◽  
Transcriptome Sequencing ◽  
High Throughput Sequencing ◽  
Lipid Production ◽  
Biodiesel Production ◽  
Oleaginous Microalgae

The oleaginous microalgae species Chlorococcum sphacosum GD is a promising feedstock for biodiesel production from soil. However, its metabolic mechanism of lipid production remains unclear. In this study, the lipid accumulation and metabolism mechanisms of Chlorococcum sphacosum GD were analyzed under salt stress based on transcriptome sequencing. The biomass and lipid content of the alga strain were determined under different NaCl concentrations, and total RNA from fresh cells were isolated and sequenced by HiSeq 2000 high throughput sequencing technology. As the salt concentration increased in culture medium, the algal lipid content increased but the biomass decreased. Following transcriptome sequencing by assembly and splicing, 24,128 unigenes were annotated, with read lengths mostly distributed in the 200–300 bp interval. Statistically significant differentially expressed unigenes were observed in different experimental groups, with 2051 up-regulated genes and 1835 down-regulated genes. The lipid metabolism pathway analysis showed that, under salt stress, gene-related fatty acid biosynthesis (ACCase, KASII, KAR, HAD, FATA) was significantly up-regulated, but some gene-related fatty acid degradation was significantly down-regulated. The comprehensive results showed that salt concentration can affect the lipid accumulation and metabolism of C. sphacosum GD, and the lipid accumulation is closely related to the fatty acid synthesis pathway.

scholarly journals The native acyltransferase-coding genes DGA1 and DGA2 affect lipid accumulation in Blastobotrys raffinosifermentans differently when overexpressed

2020 ◽  
Vol 20 (8) ◽  
Author(s):  
Daniel Ruben Akiola Sanya ◽  
Djamila Onesime ◽  
Gotthard Kunze ◽  
Cécile Neuveglise ◽  
Anne-Marie Crutz-Le Coq
Keyword(s):  
Lipid Content ◽  
Lipid Accumulation ◽  
Parental Strain ◽  
Nitrogen Limitation ◽  
Lipid Production ◽  
Strain Analysis ◽  
Ascomycetous Yeast ◽  
Transcript Levels ◽  
Dry Cell Weight

ABSTRACT Blastobotrys raffinosifermentans is an ascomycetous yeast with biotechnological applications, recently shown to be an oleaginous yeast accumulating lipids under nitrogen limitation. Diacylglycerol acyltransferases (DGATs) act in the lipid storage pathway, in the last step of triacylglycerol biosynthesis. Two DGAT families are widespread in eukaryotes. We first checked that B. raffinosifermentans strain LS3 possessed both types of DGAT, and we then overexpressed the native DGAT-encoding genes, DGA1 and DGA2, separately or together. DGA2 (from the DGAT1 family) overexpression was sufficient to increase lipid content significantly in LS3, to up to 26.5% of dry cell weight (DCW), 1.6 times the lipid content of the parental strain (16.90% of DCW) in glucose medium under nitrogen limitation. By contrast, DGA1 (of the DGAT2 type) overexpression led to a large increase (up to 140-fold) in the amount of the corresponding transcript, but had no effect on overall lipid content relative to the parental strain. Analysis of the expression of the native genes over time in the parental strain revealed that DGA2 transcript levels quadrupled between 8 and 24 h in the N-limited lipogenic medium, whereas DGA1 transcript levels remained stable. This survey highlights the predominant role of the DGAT1 family in lipid accumulation and demonstrates the suitability of B. raffinosifermentans for engineering for lipid production.

scholarly journals DGA1 (diacylglycerol acyltransferase gene) overexpression and leucine biosynthesis significantly increase lipid accumulation in the Δsnf2 disruptant of Saccharomyces cerevisiae

2007 ◽  
Vol 408 (1) ◽  
pp. 61-68 ◽  
Author(s):  
Yasushi Kamisaka ◽  
Nao Tomita ◽  
Kazuyoshi Kimura ◽  
Kumiko Kainou ◽  
Hiroshi Uemura
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Lipid Content ◽  
Lipid Accumulation ◽  
Lipid Production ◽  
Total Lipid Content ◽  
Diacylglycerol Acyltransferase ◽  
Leucine Biosynthesis ◽  
Gene Encoding ◽  
Acyltransferase Activity ◽  
Isopropylmalate Dehydrogenase

We previously found that SNF2, a gene encoding a transcription factor forming part of the SWI/SNF (switching/sucrose non-fermenting) chromatin-remodelling complex, is involved in lipid accumulation, because the Δsnf2 disruptant of Saccharomyces cerevisiae has a higher lipid content. The present study was conducted to identify other factors that might further increase lipid accumulation in the Δsnf2 disruptant. First, expression of LEU2 (a gene encoding β-isopropylmalate dehydrogenase), which was used to select transformed strains by complementation of the leucine axotroph, unexpectedly increased both growth and lipid accumulation, especially in the Δsnf2 disruptant. The effect of LEU2 expression on growth and lipid accumulation could be reproduced by adding large amounts of leucine to the culture medium, indicating that the effect was not due to Leu2p (β-isopropylmalate dehydrogenase) itself, but rather to leucine biosynthesis. To increase lipid accumulation further, genes encoding the triacylglycerol biosynthetic enzymes diacylglycerol acyltransferase (DGA1) and phospholipid:diacylglycerol acyltransferase (LRO1) were overexpressed in the Δsnf2 disruptant. Overexpression of DGA1 significantly increased lipid accumulation, especially in the Δsnf2 disruptant, whereas LRO1 overexpression decreased lipid accumulation in the Δsnf2 disruptant. Furthermore, the effect of overexpression of acyl-CoA synthase genes (FAA1, FAA2, FAA3 and FAA4), which each supply a substrate for Dga1p (diacylglycerol acyltransferase), was investigated. Overexpression of FAA3, together with that of DGA1, did not further increase lipid accumulation in the Δsnf2 disruptant, but did enhance lipid accumulation in the presence of exogenous fatty acids. Lastly, the total lipid content in the Δsnf2 disruptant transformed with DGA1 and FAA3 overexpression vectors reached approx. 30%, of which triacylglycerol was the most abundant lipid. Diacylglycerol acyltransferase activity was significantly increased in the Δsnf2 disruptant strain overexpressing DGA1 as compared with the wild-type strain overexpressing DGA1; this higher activity may account for the prominent increase in lipid accumulation in the Δsnf2 disruptant with DGA1 overexpression. The strains obtained have a lipid content that is high enough to act as a model of oleaginous yeast and they may be useful for the metabolic engineering of lipid production in yeast.

scholarly journals Transcriptional profiling reveals differentially expressed genes involved in lipid biosynthesis during cacao seed development

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Fupeng Li ◽  
Baoduo Wu ◽  
Lin Yan ◽  
Chaoyun Hao ◽  
Xiaowei Qin ◽  
...  
Keyword(s):  
Differentially Expressed Genes ◽  
Lipid Content ◽  
Lipid Accumulation ◽  
Unsaturated Fatty Acids ◽  
Transcriptional Profiling ◽  
Lipid Production ◽  
Economic Value ◽  
Lipid Synthesis ◽  
Differentially Expressed ◽  
Seed Lipid

AbstractTheobroma cacao is a plant of economic value due to the use of its seed lipid for chocolate, confectionery, and cosmetic industries. The seed lipid contains a stable ratio of saturated and unsaturated fatty acids, which determines its unique melting temperature. However, little is known about the molecular mechanism determining the fatty acid ratio and lipid content in cacao. To gain insight into the unique properties of lipid synthesis in cacao, biochemical and transcriptomic approaches were used to compare the lipid accumulation between high and low lipid content cacao accessions. Lipid accumulation rates and lipid content were different between the two accessions. Moreover, differentially expressed genes were detected between high and low lipid content cacao accessions. The data allowed the identification of distinct candidate genes and furthered our understanding of lipid accumulation, potentially explaining the differences in lipid content between various cacao accessions. The results might be used to develop molecular tools and engineer alternative pathways for cacao breeding with improved lipid production potentials.

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