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Yu J, You X, Wang Y, Jin C, Zhao Y, Guo L. Focus on the role of synthetic phytohormone for mixotrophic growth and lipid accumulation by Chlorella pyrenoidosa. CHEMOSPHERE 2022; 308:136558. [PMID: 36150488 DOI: 10.1016/j.chemosphere.2022.136558] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 08/26/2022] [Accepted: 09/17/2022] [Indexed: 06/16/2023]
Abstract
Synthetic phytohormone (SP) is regarded as an attractive candidate for microalgae cultivation due to its potential for high-value microalgae biomass production. Herein, α-naphthylacetic acid (NAA), indomethacin (IN) and 2,4-dichlorophenoxyacetic acid (2,4-D) were used for the mixotrophic cultivation of Chlorella pyrenoidosa with mariculture wastewater (MW) acidogenic fermentation effluent. The growth and lipid accumulation of Chlorella pyrenoidosa added with SP were enhanced, given their high bioavailability of the nutrients. Among these three SPs, IN was optimal for Chlorella pyrenoidosa growth, with the maximum optical density of 1.81. NAA exhibited the best performance for lipid production and the proportion of lipid reached 50.24%. Furthermore, the energy of Chlorella pyrenoidosa cultured with SP preferentially allocated to lipogenesis. To understand the mechanism of lipid accumulation in Chlorella pyrenoidosa in response to SP, the enzyme activities involved in carbon metabolism were determined. The malic enzyme (ME) and acetyl-CoA carboxylase (ACCase) were positively correlated with lipid accumulation. Phosphoenolpyruvate carboxylase (PEPC) was the negative feedback enzyme for lipid synthesis. The findings could provide valuable information for regulation mechanism of lipid accumulation and value-added products recovery by microalgae.
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Affiliation(s)
- Jinghan Yu
- College of Environmental Science and Engineering, Ocean University of China, Qingdao, 266100, China
| | - Xuting You
- College of Environmental Science and Engineering, Ocean University of China, Qingdao, 266100, China
| | - Yi Wang
- Department of Biosystems Engineering, Auburn University, Auburn, AL 36849, United States
| | - Chunji Jin
- College of Environmental Science and Engineering, Ocean University of China, Qingdao, 266100, China
| | - Yangguo Zhao
- College of Environmental Science and Engineering, Ocean University of China, Qingdao, 266100, China
| | - Liang Guo
- College of Environmental Science and Engineering, Ocean University of China, Qingdao, 266100, China; Key Laboratory of Marine Environmental and Ecology, Ministry of Education, Ocean University of China, Qingdao, 266100, China.
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Dalby FR, Guldberg LB, Feilberg A, Kofoed MVW. Reducing greenhouse gas emissions from pig slurry by acidification with organic and inorganic acids. PLoS One 2022; 17:e0267693. [PMID: 35511811 PMCID: PMC9070912 DOI: 10.1371/journal.pone.0267693] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 04/13/2022] [Indexed: 11/24/2022] Open
Abstract
Methane (CH4) emission from pig slurry is a large contributor to the climate footprint of livestock production. Acidification of excreta from livestock animals with sulfuric acid, reduce CH4 emission and is practiced at many Danish farms. Possible interaction effects with other acidic agents or management practices (e.g. frequent slurry removal and residual slurry acidification) have not been fully investigated. Here we assessed the effect of pig slurry acidification with a range of organic and inorganic acids with respect to their CH4 inhibitor potential in several batch experiments (BS). After careful selection of promising CH4 inhibitors, three continuous headspace experiments (CHS) were carried out to simulate management of manure in pig houses. In BS experiments, more than <99% CH4 reduction was observed with HNO3 treatment to pH 5.5. Treatments with HNO3, H2SO4, and H3PO4 reduced CH4 production more than acetic acid and other organic acids when acidified to the same initial pH of 5.5. Synergistic effects were not observed when mixing inorganic and organic acids as otherwise proposed in the literature, which was attributed to the high amount of acetic acid in the slurry to start with. In the CHS experiments, HNO3 treatment reduced CH4 more than H2SO4, but increased nitrous oxide (N2O) emission, particularly when the acidification target pH was above 6, suggesting considerable denitrification activity. Due to increased N2O emission from HNO3 treatments, HNO3 reduced total CO2-eq by 67%, whereas H2SO4 reduced CO2-eq by 91.5% compared to untreated slurry. In experiments with daily slurry addition, weekly slurry removal, and residual acidification, HNO3 and H2SO4 treatments reduced CO2-eq by 27% and 48%, respectively (not significant). More cycles of residual acidification are recommended in future research. The study provides solid evidence that HNO3 treatment is not suitable for reducing CO2-eq and H2SO4 should be the preferred acidic agent for slurry acidification.
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Affiliation(s)
- Frederik R. Dalby
- Department of Biotechnology and Chemical Engineering, Faculty of Technical Science, Aarhus University, Aarhus, Denmark
- * E-mail:
| | - Lise B. Guldberg
- Department of Biotechnology and Chemical Engineering, Faculty of Technical Science, Aarhus University, Aarhus, Denmark
| | - Anders Feilberg
- Department of Biotechnology and Chemical Engineering, Faculty of Technical Science, Aarhus University, Aarhus, Denmark
| | - Michael V. W. Kofoed
- Department of Biotechnology and Chemical Engineering, Faculty of Technical Science, Aarhus University, Aarhus, Denmark
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Gao P, Guo L, Gao M, Zhao Y, Jin C, She Z. Regulation of carbon source metabolism in mixotrophic microalgae cultivation in response to light intensity variation. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2022; 302:114095. [PMID: 34775333 DOI: 10.1016/j.jenvman.2021.114095] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Revised: 10/14/2021] [Accepted: 11/09/2021] [Indexed: 06/13/2023]
Abstract
Microalgae are one of the promising sources for renewable energy production, and the light intensity variation can affect the biofuel generation and carbon assimilation of mixotrophic microalgae. To reveal the response of carbon assimilation to light intensity, the effect of light intensity on the carbon source metabolism of Chlorella vulgaris under mixotrophic cultivation was investigated in this study. Moreover, the optimal carbon source composition for mixotrophic microalgae cultivation was evaluated using bicarbonate (HCO3-) and carbonate (CO32-) as inorganic carbon sources, and glucose and acetate as organic carbon sources. The optimal light intensity for Chlorella vulgaris growth was at the range of 8000-12000 lux. For the accumulation of biochemical components, low light intensity was beneficial to protein accumulation, and high light intensity was advantageous for carbohydrate and lipid accumulation. With HCO3- and glucose, the maximum lipid content reached 37.0% at a light intensity of 12000 lux. The citrate synthase activity was negatively correlated with light intensity, showing an opposite trend to biomass production. High light intensity had a positive impact on Rubisco expression, which promoted the microalgae growth and carbon fixing. The energy produced by heterotrophic metabolic activities increased at low light intensity, and the enhancement of biomass production with high light intensity was mainly caused by the improved photoreaction efficiency during the mixotrophic cultivation.
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Affiliation(s)
- Pengtao Gao
- College of Environmental Science and Engineering, Ocean University of China, Qingdao, 266100, China; Department of Chemical Engineering, KU Leuven, Celestijnenlaan 200F, B-3001, Leuven, Belgium
| | - Liang Guo
- College of Environmental Science and Engineering, Ocean University of China, Qingdao, 266100, China; Key Laboratory of Marine Environmental and Ecology, Ministry of Education, Ocean University of China, Qingdao, 266100, China; Shandong Provincial Key Laboratory of Marine Environment and Geological Engineering, Ocean University of China, Qingdao, 266100, China.
| | - Mengchun Gao
- College of Environmental Science and Engineering, Ocean University of China, Qingdao, 266100, China
| | - Yangguo Zhao
- College of Environmental Science and Engineering, Ocean University of China, Qingdao, 266100, China
| | - Chunji Jin
- College of Environmental Science and Engineering, Ocean University of China, Qingdao, 266100, China
| | - Zonglian She
- College of Environmental Science and Engineering, Ocean University of China, Qingdao, 266100, China
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Ali MM, Mustafa AM, Zhang X, Zhang X, Danhassaan UA, Lin H, Choe U, Wang K, Sheng K. Combination of ultrasonic and acidic pretreatments for enhancing biohythane production from tofu processing residue via one-stage anaerobic digestion. BIORESOURCE TECHNOLOGY 2022; 344:126244. [PMID: 34732374 DOI: 10.1016/j.biortech.2021.126244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 10/24/2021] [Accepted: 10/26/2021] [Indexed: 06/13/2023]
Abstract
Tofu processing residues (TPR) have received more attention as a source of bioenergy. However, their low solubility has hindered biohythane generation. Consequently, the ultrasonic and H2SO4 pretreatments were combined and compared for the first time to improve the hydrolysis of organic matter and carbohydrate and increase free amino nitrogen generation from TPR. Besides, the impact of pretreatments on biohythane generation was investigated. Under the optimal conditions of 7.54% substrate level, 8% H2SO4 concentration, 80 °C and 50 min, the coincident ultrasonic-H2SO4 pretreatment enriched the contents of soluble chemical oxygen demand, reducing sugar, and free amino nitrogen to 49675 mg/L, 26 g/L, and 1721 mg/L, respectively, greater than individual pretreatments. Also, Biohythane yield increased by 4.24-13.61% over control (389.42 ± 23.7 ml/g-VSfed). Furthermore, hydrogen yield at 42.5 ± 2.08 and 28.1 ± 1.07 ml/g-VSfed and sulfate removal efficiency at 93 and 92% were significantly improved with ultrasonic-H2SO4 and H2SO4 pretreatments, respectively, indicating acidogenic and sulfidogenic activity enhancement.
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Affiliation(s)
- Mahmoud M Ali
- College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310058, China; Biological Engineering Department, Agricultural Engineering Research Institute, Giza, Egypt
| | - Ahmed M Mustafa
- State Key Laboratory of Pollution Control and Recourses Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Department of Agricultural Engineering, Faculty of Agriculture, Suez Canal University, Ismailia 41522, Egypt
| | - Ximing Zhang
- College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310058, China
| | - Xin Zhang
- College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310058, China
| | - Umar A Danhassaan
- College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310058, China
| | - Hongjian Lin
- College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310058, China
| | - Ungyong Choe
- College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310058, China; Faculty of Environmental Science, University of Science, Yusheng Scientist Road, Unjong 13 District, Pyongyang 00850, Democratic People's Republic of Korea
| | - Kaiying Wang
- College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310058, China
| | - Kuichuan Sheng
- College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310058, China.
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Im S, Mostafa A, Shin SR, Kim DH. Combination of H 2SO 4-acidification and temperature-decrease for eco-friendly storage of pig slurry. JOURNAL OF HAZARDOUS MATERIALS 2020; 399:123063. [PMID: 32512282 DOI: 10.1016/j.jhazmat.2020.123063] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 05/09/2020] [Accepted: 05/25/2020] [Indexed: 06/11/2023]
Abstract
Owing to the economic benefit and efficiency, H2SO4-acidification is often applied for reducing CH4 emissions during storage of pig slurry (PS). However, it encounters with several problems related with safety and the concomitant H2S emissions. To reduce the required amount of H2SO4, in this study, the storage at low temperature (20-35 °C) was applied to the mild-acidified PS (pH 6.5 and 7.0). 55.1 kg CO2 eq./ton PS of CH4 was emitted from the control (non-acidified at 35 °C), which was reduced to 14.4-40.2 kg CO2 eq./ton PS at 20-30 °C. Temperature-decrease led to the increase of the abundance of methanogens (Methanobrevibacter and Methanolobus) that can grow at low temperature and the drop of specific methanogenic activity value. To achieve 70 % CH4 reduction, 1.6 kg H2SO4/ton PS was needed in PS acidification, which was decreased to 0.5 kg H2SO4/ton PS by decreasing temperature from 35 °C to 25 °C. CH4 production potential of the PS stored at 35 °C-pH 6.5 and 25 °C-pH 7.0 was increased by 21-33 % compared to the control. The GHG reduction of 33.6-41.9 kg CO2 eq./ton PS and the profit of 6.6 USD/ton PS could be attained by applying acidification or combined storage, indicating that the temperature-decrease can be effectively combined with H2SO4-acidification.
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Affiliation(s)
- Seongwon Im
- Department of Civil Engineering, Inha University, 100 Inharo, Nam-gu, Incheon 22212, Republic of Korea
| | - Alsayed Mostafa
- Department of Civil Engineering, Inha University, 100 Inharo, Nam-gu, Incheon 22212, Republic of Korea
| | - Sang-Ryong Shin
- Process design team, JEON TECH. Co., Ltd., 77 Haenggung-ro, Paldal-gu, Suwon 16261, Republic of Korea
| | - Dong-Hoon Kim
- Department of Civil Engineering, Inha University, 100 Inharo, Nam-gu, Incheon 22212, Republic of Korea.
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