Effect of biomass concentration on secondary carotenoids and triacylglycerol (TAG) accumulation in nitrogen-depleted Chlorella zofingiensis

Three Circulating Floating Bed Reactors (CFBR) R1, R2 and R3 with 20% v/v of a plastic carrier with different size distribution were operated to study the effect of the particles size of the carrier on biomass accumulation and nitrification performance. Operating conditions were similar in the three systems: ammonia concentrations around 50 mg-N–NH4+/ L, ammonia loading rates up to 1.2 kg N–NH4+/m3·d and temperatures between 14 and 27°C. Accumulation of nitrite was observed until day 65th. This w as result both of the inhibition of nitrite oxidation by free ammonia until day 20th and the insignificant accumulation of a biomass with low nitrite oxidising capacity between days 20 and 65th. Ammonia conversion rate and removal efficiency were higher in the reactor with lower particle size, R3 (nitrification rate of 1.1 kg N–NH4+/m3·d and ammonia removal of 97% at 16°C), than in R2 or R1 (nitrification rate of 1.0 kg N–NH4+/m3·d and ammonia removal of 90% at 16°C). The better efficiency in R3 was obtained as a result of the higher specific surface of the biofilm developed. Biomass activity was similar in the three reactors (2.2 and 1.12 g N/g protein · d at 30 and 15°C, respectively). Both the biomass evolution with time and biomass retention in the systems was practically not influenced by the size of particle. Biomass concentration of 1.2 g protein/L was retained in the carrier and up to 20% of the newly produced biomass was retained in the CFBRs.

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Assimilation of various organic carbon sources by Haematococcus strains

Acta Agronomica Hungarica ◽

10.1556/aagr.57.2009.2.14 ◽

2009 ◽

Vol 57 (2) ◽

pp. 231-237

Author(s):

M. Zych ◽

A. Stolarczyk ◽

K. Maca ◽

A. Banaś ◽

K. Termińska-Pabis ◽

...

Keyword(s):

Organic Carbon ◽

Organic Compounds ◽

Present Experiment ◽

Carbon Sources ◽

Growth Conditions ◽

Mixotrophic Growth ◽

Naturally Occurring ◽

Organic Carbon Sources ◽

Secondary Carotenoids ◽

Colour Changes

Differences in the assimilation of individual organic compounds (5 mM sugars and L-asparagine) under mixotrophic growth conditions were described for three naturally occurring Haematococcus strains.The effects of assimilation were measured by the growth intensity and size of algal cells, and the effect of colour changes in the cultures was observed. Some compounds caused the cell colouration to change from green to yellow, being the result of chlorophyll disappearance and the accumulation of yellow secondary carotenoids. In the present experiment none of the cultures turned red, thus excluding the intense accumulation of the commercially interesting carotenoid, astaxanthin.

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A Mathematical Model for the Anaerobic Digestion Process Applied to a Mixture of Night Soil and Septic Tank Sludge

Water Science & Technology ◽

10.2166/wst.1986.0295 ◽

1986 ◽

Vol 18 (7-8) ◽

pp. 239-248 ◽

Cited By ~ 2

Author(s):

Sung Ryong Ha ◽

Dwang Ho Lee ◽

Sang Eun Lee

Keyword(s):

Mathematical Model ◽

Anaerobic Digestion ◽

Biomass Concentration ◽

Gas Production ◽

Septic Tank ◽

Volatile Acid ◽

Hydraulic Residence Time ◽

Anaerobic Digestion Process ◽

Digestion Process ◽

Proposed Model

Laboratory scale experiments were conducted to develop a mathematical model for the anaerobic digestion of a mixture of night soil and septic tank sludge. The optimum mixing ratio by volume between night soil and septic tank sludge was found to be 7:3. Due to the high solids content in the influent waste, mixed-liquor volatile suspended solids (MLVSS) was not considered to be a proper parameter for biomass concentration, therefore, the active biomass concentration was estimated based on deoxyribonucleic acid (DNA) concentration in the reactor. The weight ratio between acidogenic bacteria and methanogenic bacteria in the mixed culture of a well-operated anaerobic digester was approximately 3:2. The proposed model indicates that the amount of volatile acid produced and the gas production rate can be expressed as a function of hydraulic residence time (HRT). The kinetic constants of the two phases of the anaerobic digestion process were determined, and a computer was used to simulate results using the proposed model for the various operating parameters, such as BOD5 and volatile acid concentrations in effluent, biomass concentrations and gas production rates. These were consistent with the experimental data.

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Nordic cyanobacterial and algal lipids: TAG accumulation, chemotaxonomy and bioindustrial potential

Physiologia Plantarum ◽

10.1111/ppl.13443 ◽

2021 ◽

Author(s):

Anita Santana‐Sánchez ◽

Fiona Lynch ◽

Sema Şirin ◽

Yagut Allahverdiyeva

Keyword(s):

Tag Accumulation

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Xanthophylls from the Sea: Algae as Source of Bioactive Carotenoids

Marine Drugs ◽

10.3390/md19040188 ◽

2021 ◽

Vol 19 (4) ◽

pp. 188

Author(s):

Antia G. Pereira ◽

Paz Otero ◽

Javier Echave ◽

Anxo Carreira-Casais ◽

Franklin Chamorro ◽

...

Keyword(s):

Haematococcus Pluvialis ◽

Biological Effects ◽

Algal Species ◽

Antioxidant Properties ◽

Laminaria Japonica ◽

Chlorella Zofingiensis ◽

Brown Seaweeds ◽

Extraction And Purification ◽

Available Information ◽

Large Groups

Algae are considered pigment-producing organisms. The function of these compounds in algae is to carry out photosynthesis. They have a great variety of pigments, which can be classified into three large groups: chlorophylls, carotenoids, and phycobilins. Within the carotenoids are xanthophylls. Xanthophylls (fucoxanthin, astaxanthin, lutein, zeaxanthin, and β-cryptoxanthin) are a type of carotenoids with anti-tumor and anti-inflammatory activities, due to their chemical structure rich in double bonds that provides them with antioxidant properties. In this context, xanthophylls can protect other molecules from oxidative stress by turning off singlet oxygen damage through various mechanisms. Based on clinical studies, this review shows the available information concerning the bioactivity and biological effects of the main xanthophylls present in algae. In addition, the algae with the highest production rate of the different compounds of interest were studied. It was observed that fucoxanthin is obtained mainly from the brown seaweeds Laminaria japonica, Undaria pinnatifida, Hizikia fusiformis, Sargassum spp., and Fucus spp. The main sources of astaxanthin are the microalgae Haematococcus pluvialis, Chlorella zofingiensis, and Chlorococcum sp. Lutein and zeaxanthin are mainly found in algal species such as Scenedesmus spp., Chlorella spp., Rhodophyta spp., or Spirulina spp. However, the extraction and purification processes of xanthophylls from algae need to be standardized to facilitate their commercialization. Finally, we assessed factors that determine the bioavailability and bioaccesibility of these molecules. We also suggested techniques that increase xanthophyll’s bioavailability.

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Effect of magnetic field on biomass properties and their role in biodegradation under condition of low dissolved oxygen

Applied Water Science ◽

10.1007/s13201-021-01439-9 ◽

2021 ◽

Vol 11 (7) ◽

Author(s):

Nur Syamimi Zaidi ◽

Johan Sohaili ◽

Khalida Muda ◽

Mika Sillanpää ◽

Norelyza Hussein

Keyword(s):

Magnetic Field ◽

Dissolved Oxygen ◽

Biomass Concentration ◽

Aerobic Bacteria ◽

Batch Reactors ◽

Sequencing Batch Reactors ◽

Great Chance ◽

Sludge Bulking ◽

The Magnetic Field ◽

High Biomass Concentration

AbstractLow condition of dissolved oxygen (DO) is commonly associated with sludge bulking problem that was able to disrupt the efficiency of wastewater treatment performances. Relatively, very little attention was paid to the possibility of applying magnetic field in controlling the bulking problem. Hence, this study aims to investigate the performance of magnetic field on biomass properties and its effect on biodegradation under low condition of DO. Two continuous laboratory-scale sequencing batch reactors—Reactor A (SBRA) and Reactor B (SBRB)—were setup. SBRA was equipped with the magnetic device to exhibit magnetic field of 88 mT, while SBRB acted as a control system. The results showed that the biomass concentration in SBRA was higher compared to SBRB. High biomass concentration in SBRA resulted to better settleability with mean SVI of less than 30 mL/g. SBRA also showed consistently high removal performances of organic and inorganic contents compared to SBRB. These observations confirmed that the magnetic field was able to enhance the biomass properties, which further enhance the biodegradation ability of the aerobic bacteria under low DO condition. This also indicates that under the sludge bulking circumstances, the use of magnetic field stands a great chance in maintaining high biodegradation of the treatment system.

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Sirtuin 3 Restores Synthesis and Secretion of Very Low-Density Lipoproteins in Cow Hepatocytes Challenged with Nonesterified Fatty Acids In Vitro

Veterinary Sciences ◽

10.3390/vetsci8070121 ◽

2021 ◽

Vol 8 (7) ◽

pp. 121

Author(s):

Dongmei Xing ◽

Baogen Wang ◽

Hong Lu ◽

Tao Peng ◽

Jianming Su ◽

...

Keyword(s):

Fatty Acids ◽

Dairy Cows ◽

Low Density Lipoproteins ◽

Mrna Abundance ◽

Low Density ◽

Sirtuin 3 ◽

Very Low Density Lipoproteins ◽

Nonesterified Fatty Acids ◽

Tag Accumulation

Fatty liver is closely associated with elevated concentrations of nonesterified fatty acids (NEFA) and a low level of very low-density lipoproteins (VLDL) in blood of dairy cows. High NEFA inhibit the VLDL synthesis and assembly, and cause hepatic triacylglycerol (TAG) deposition. Sirtuin 3 (SIRT3), a mitochondrial deacetylase, antagonizes NEFA-induced TAG accumulation through modulating expressions of fatty acid synthesis and oxidation genes in cow hepatocytes. However, the role of SIRT3 in the VLDL synthesis and assembly was largely unknown. Here we aimed to test whether SIRT3 would recover the synthesis and assembly of VLDL in cow hepatocytes induced by high NEFA. Primary cow hepatocytes were isolated from 3 Holstein cows. Hepatocytes were infected with SIRT3 overexpression adenovirus (Ad-SIRT3), SIRT3-short interfering (si) RNA, or first infected with Ad-SIRT3 and then incubated with 1.0 mM NEFA (Ad-SIRT3 + NEFA). Expressions of key genes in VLDL synthesis and the VLDL contents in cell culture supernatants were measured. SIRT3 overexpression significantly increased the mRNA abundance of microsomal triglyceride transfer protein (MTP), apolipoprotein B100 (ApoB100) and ApoE (p < 0.01), and raised VLDL contents in the supernatants (p < 0.01). However, SIRT3 silencing displayed a reverse effect in comparison to SIRT3 overexpression. Compared with NEFA treatment alone, the Ad-SIRT3 + NEFA significantly upregulated the mRNA abundance of MTP, ApoB100 and ApoE (p < 0.01), and increased VLDL contents in the supernatants (p < 0.01). Our data demonstrated that SIRT3 restored the synthesis and assembly of VLDL in cow hepatocytes challenged with NEFA, providing an in vitro basis for further investigations testing its feasibility against hepatic TAG accumulation in dairy cows during the perinatal period.

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