Influence of Sulfur and Light Intensity in Nutrient Removal, and Hydrogen and Ethanol Production by Optimized Biomass of Chlamydomonas Reinhardtii in Batch Anaerobic Photobioreactors

Abstract Hydrogen is a renewable fuel that can be biologically produced by green algae in closed anaerobic photobioreactors with light and organic carbon as energy sources. This research aimed to investigate the influence of sulfur concentration and light intensity on hydrogen and ethanol production, as well as on nutrient removal by Chlamydomonas reinhardtii (CC425) in batch cultures. The strain was cultivated in two phases: in the first step, the cultures were maintained under aerobic conditions to obtain biomass; in the second step, the biomass was transferred to closed anaerobic photobioreactors for gas generation under continuous illumination. A factorial design was accomplished to optimize the biomass production in the first step, with light variation, pH, and glucose addition. Afterward, light intensity and sulfur concentration were varied to test hydrogen production in the second step. The best production occurred in photobioreactors without sulfur addition (average increase of 7 times in the production) and under higher light intensity the production was 37% higher than lower light (39.64 ± 2.44 µmol H2 L-1 h-1). There was an effect of sulfur concentration in the ethanol production and under higher light intensity the production was higher (203.20 ± 31.49 mg L-1). In addition, in general, under conditions with the presence of sulfur, there was greater removal of ammoniacal nitrogen (5.3%), phosphate (85.0%), COD (9.1%) and acetic acid (97.2%). This research demonstrates the efficient production of hydrogen and ethanol by C. reinhardtii and it shows that the process can be associated with nutrient removal.

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Influence of Sulfur and Light Intensity in Nutrient Removal, and Hydrogen and Ethanol Production by Improved Biomass of Chlamydomonas reinhardtii in Batch Anaerobic Photobioreactors

BioEnergy Research ◽

10.1007/s12155-021-10296-y ◽

2021 ◽

Author(s):

Sarah Regina Vargas ◽

Marcelo Zaiat ◽

Maria do Carmo Calijuri

Keyword(s):

Light Intensity ◽

Chlamydomonas Reinhardtii ◽

Ethanol Production ◽

Nutrient Removal

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P6595The optogenetic defibrillation of ventricular arrhythmia in myocardial infarction rats in vivo

European Heart Journal ◽

10.1093/eurheartj/ehz746.1183 ◽

2019 ◽

Vol 40 (Supplement_1) ◽

Author(s):

X I Wang ◽

Y Cheng ◽

P Rao ◽

L Wang

Keyword(s):

Light Intensity ◽

Ventricular Arrhythmia ◽

Sinus Rhythm ◽

Pulse Duration ◽

Underlying Mechanism ◽

Blue Laser ◽

Continuous Illumination ◽

Threshold Intensity ◽

Systemic Delivery ◽

Significant Difference

Abstract Introduction Optogenetics is a low-invasive, flexible and highly selective intervention that enables electrical excitation with light on myocardium overexpressing light-sensitive proteins. Optical illumination can control the simultaneous exciting of the whole myocardium under the spot, which is more conducive to recovery from electrical disturbance to sinus rhythm. Purpose We explored optogenetic defibrillation for different illumination parameters how to affect defibrillation rates and the possible mechanism of continuous illumination defibrillation. Methods Systemic delivery via right jugular vein injection of (AAV9-CAG-hChR2(H134R)-mCherry) were performed in juvenile SD rats to achieve the light sensitive protein Channelrhodopsin-2 (ChR2) transfer throughout the whole heart. We intubated and ventilated rats, opened chest and recorded the ECG. After ligation of the left anterior descending coronary artery, ventricular arrhythmia was induced by electrical burst stimulation (10v, 50Hz, 2s). Cardiac epicardium illumination with 470nm blue laser was performed to investigate the effects of optogenetic defibrillation and its underlying mechanism. Every heart accepted 30 pulses of 20ms duration on 8Hz to test the light intensity threshold for 1:1 capture. Different illumination modes of multiple light intensity (2,4,8,10,20 times threshold intensity), pulse duration (20, 50, 200, 500 and 1000ms) and illumination position (RV apex, RV, RVOT, septum, LV) were applied in each attempt for 4 repetitions with 1 s interval. Results We demonstrated that ventricular arrhythmias could be terminated by illumination of the right ventricle at 20 times threshold intensity in 1s (figure A) with the successful defibrillation rate of 95±2.673% (mean ±SEM; N=7). Herein, the successful optogenetic defibrillation rate was strongly depending on light intensity (N=5, n=50 episodes, p=0.0118) and duration of illumination (N=5, n=50 episodes, p<0.0001) (figure B.C). Notably when there were higher intensity and longer pulse duration, the higher defibrillation rate appeared. There was no significant difference in the defibrillation rate among different illumination positions (N=5, n=25episodes per position, p=0.1177) (figure D). To explore the underlying mechanism of optogenetic defibrillation, we performed the same illumination mode during sinus rhythm in 2 rats (figure E. F. G). We observed that higher light intensity and longer pulse duration were more conducive to induce an episode of higher frequency focal excitement. Views of optogenetic defibrillation Conclusions We demonstrated that optogenetic defibrillation is a highly effective intervention and the possible mechanism is partly attributed to overdrive suppression. We believe that optogenetic approach is potentially to be translated into more efficient and pain-free clinical termination of ventricular arrhythmia. Acknowledgement/Funding The national natural science foundation of China (81772044)

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Hydrogen production from water electrolysis: role of catalysts

Nano Convergence ◽

10.1186/s40580-021-00254-x ◽

2021 ◽

Vol 8 (1) ◽

Author(s):

Shan Wang ◽

Aolin Lu ◽

Chuan-Jian Zhong

Keyword(s):

Hydrogen Production ◽

Water Splitting ◽

Noble Metal ◽

Active Sites ◽

Current Knowledge ◽

Low Cost ◽

Critical Role ◽

Water Electrolysis ◽

Efficient Production ◽

Production Of Hydrogen

AbstractAs a promising substitute for fossil fuels, hydrogen has emerged as a clean and renewable energy. A key challenge is the efficient production of hydrogen to meet the commercial-scale demand of hydrogen. Water splitting electrolysis is a promising pathway to achieve the efficient hydrogen production in terms of energy conversion and storage in which catalysis or electrocatalysis plays a critical role. The development of active, stable, and low-cost catalysts or electrocatalysts is an essential prerequisite for achieving the desired electrocatalytic hydrogen production from water splitting for practical use, which constitutes the central focus of this review. It will start with an introduction of the water splitting performance evaluation of various electrocatalysts in terms of activity, stability, and efficiency. This will be followed by outlining current knowledge on the two half-cell reactions, hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), in terms of reaction mechanisms in alkaline and acidic media. Recent advances in the design and preparation of nanostructured noble-metal and non-noble metal-based electrocatalysts will be discussed. New strategies and insights in exploring the synergistic structure, morphology, composition, and active sites of the nanostructured electrocatalysts for increasing the electrocatalytic activity and stability in HER and OER will be highlighted. Finally, future challenges and perspectives in the design of active and robust electrocatalysts for HER and OER towards efficient production of hydrogen from water splitting electrolysis will also be outlined.

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Pigment Production under Cold Stress in the Green Microalga Chlamydomonas reinhardtii

Agriculture ◽

10.3390/agriculture11060564 ◽

2021 ◽

Vol 11 (6) ◽

pp. 564

Author(s):

Supakorn Potijun ◽

Chonlada Yaisamlee ◽

Anchalee Sirikhachornkit

Keyword(s):

Cold Stress ◽

Chlamydomonas Reinhardtii ◽

Production Efficiency ◽

Cell Physiology ◽

Efficient Production ◽

Increase Production Efficiency ◽

Whole Cells ◽

Stress Acclimation ◽

Chlorophyll Accumulation ◽

In The Wild

Microalgae have long been used for the commercial production of natural colorants such as carotenoids and chlorophyll. Due to the rising demand for carotenoids and other natural products from microalgae, strategies to increase production efficiency are urgently needed. The production of microalgal biorefineries has been limited to countries with moderate climates. For countries with cooler climates and less daylight, methodologies for the efficient production of microalgal biorefineries need to be investigated. Algal strains that can be safely consumed as whole cells are also attractive alternatives for developing as carotenoid supplements, which can also contain other compounds with health benefits. Using such strains helps to eliminate the need for hazardous solvents for extraction and several other complicated steps. In this study, the mesophilic green alga Chlamydomonas reinhardtii was employed to study the effects of cold stress on cell physiology and the production of pigments and storage compounds. The results showed that temperatures between 10 and 20 °C induced carotenoid and chlorophyll accumulation in the wild-type strain of C. reinhardtii. Interestingly, the increased level of carotenoids suggested that they might play a crucial role in cold stress acclimation. A temperature of 15 °C resulted in the highest carotenoid and chlorophyll productivity. At this temperature, carotenoid and chlorophyll productivity was 2 times and 1.3 times higher than at 25 °C, respectively. Subjecting a mutant defective in lutein and zeaxanthin accumulation to cold stress revealed that these two carotenoids are not essential for cold stress survival. Therefore, cold temperature could be used as a strategy to induce and increase the productivity of pigments in C. reinhardtii.

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Ni-Co single atomic anchored conjugated microporous polymer for high-performance photocatalytic hydrogen evolution

Journal of Materials Chemistry A ◽

10.1039/d1ta02547c ◽

2021 ◽

Author(s):

Chen Yang ◽

Zhonghua Cheng ◽

Giorgio Divitini ◽

Cheng Qian ◽

Bo Hou ◽

...

Keyword(s):

Hydrogen Evolution ◽

High Performance ◽

Efficient Production ◽

Gaseous Diffusion ◽

Photocatalytic Hydrogen Evolution ◽

Conjugated Microporous Polymer ◽

Microporous Polymer ◽

Production Of Hydrogen ◽

Simple Pathway

The fabrication of single atomic photocatalysts via a simple pathway is a crucial challenge to enable efficient production of hydrogen. Herein, we demonstrate a gaseous diffusion strategy to construct single...

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