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He Z, Zhou X, Mei N, Jin W, Sun J, Yin S, Wang Q. Effectiveness of cyclic treatment of municipal wastewater by Tetradesmus obliquus - Loofah biofilm, its internal community changes and potential for resource utilization. WATER RESEARCH X 2024; 24:100254. [PMID: 39281025 PMCID: PMC11402319 DOI: 10.1016/j.wroa.2024.100254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/06/2024] [Revised: 07/21/2024] [Accepted: 08/28/2024] [Indexed: 09/18/2024]
Abstract
Microalgae biofilm has garnered significant attention from researchers in the field of sewage treatment due to its advantages such as ease of collection and stable sewage treatment capabilities. Using agricultural waste as biofilm carriers has become a hotspot in reducing costs for this method. This study first combined Tetradesmus obliquus with loofah to form a microalgae biofilm for the study of periodic nitrogen and phosphorus removal from municipal wastewater. The biofilm could stably treat 7 batches of wastewater within one month. The removal rate of TP almost reached 100 %, while the removal rates of NH4 + and TN both reached or exceeded 80 %. The average biomass yield over 25 days was 102.04 mg/L/day. The polysaccharide content increased from 8.61 % to 16.98 % during the cyclic cultivation. The lipid content gradually decreased from 40.91 to 26.1 %. The protein content increased from 32.93 % in the initial stage to 41.18 % and then decreased to 36.31 % in the later stage. During the mid-stage of culturing, the richness of anaerobic bacteria decreased, while the richness of aerobic and facultative bacteria increased, which was conducive to the construction of the microalgae-bacteria symbiotic system and steadily improved the effect of nitrogen and phosphorus removal. As the culturing progressed, the Rotifers that emerged during the mid-stage gradually damaged the biofilm over time, leading to a decline in the effectiveness of sewage treatment in the later stages. This study offers technical support for carrier selection in microalgae biofilm methods and for the periodic removal of nitrogen and phosphorus from wastewater.
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Affiliation(s)
- Zhongqi He
- State Key Laboratory of Urban Water Resource and Environment, School of Civil and Environmental Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen, Guangdong 518055, China
| | - Xu Zhou
- State Key Laboratory of Urban Water Resource and Environment, School of Civil and Environmental Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen, Guangdong 518055, China
| | - Nannan Mei
- State Key Laboratory of Urban Water Resource and Environment, School of Civil and Environmental Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen, Guangdong 518055, China
| | - Wenbiao Jin
- State Key Laboratory of Urban Water Resource and Environment, School of Civil and Environmental Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen, Guangdong 518055, China
| | - Jing Sun
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Shiyu Yin
- State Key Laboratory of Urban Water Resource and Environment, School of Civil and Environmental Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen, Guangdong 518055, China
| | - Qilin Wang
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Ultimo, NSW 2007, Australia
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2
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Xu P, Shao S, Qian J, Li J, Xu R, Liu J, Zhou W. Scale-up of microalgal systems for decarbonization and bioproducts: Challenges and opportunities. BIORESOURCE TECHNOLOGY 2024; 398:130528. [PMID: 38437968 DOI: 10.1016/j.biortech.2024.130528] [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: 01/11/2024] [Revised: 03/01/2024] [Accepted: 03/01/2024] [Indexed: 03/06/2024]
Abstract
The threat of global climate change presents a significant challenge for humanity. Microalgae-based carbon capture and utilization (CCU) technology has emerged as a promising solution to this global issue. This review aims to comprehensively evaluate the current advancements in scale-up of microalgae cultivation and its applications, specifically focusing on decarbonization from flue gases, organic wastewater remediation, and biogas upgrading. The study identifies critical challenges that need to be addressed during the scale-up process and evaluates the economic viability of microalgal CCU within the carbon market. Additionally, it analyzes the commercial status of microalgae-derived products and highlights those with high market demand. This review serves as a crucial resource for researchers, industry professionals, and policymakers to develop and implement innovative approaches to enhance the efficiency of microalgae-based CO2 utilization while addressing the challenges associated with the scale-up of microalgae technologies.
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Affiliation(s)
- Peilun Xu
- Key Laboratory of Poyang Lake Environment and Resource Utilization, Ministry of Education, and Center for Algae Innovation & Engineering Research, School of Resources & Environment, Nanchang University, Nanchang 330031, China.
| | - Shengxi Shao
- Key Laboratory of Poyang Lake Environment and Resource Utilization, Ministry of Education, and Center for Algae Innovation & Engineering Research, School of Resources & Environment, Nanchang University, Nanchang 330031, China.
| | - Jun Qian
- Key Laboratory of Poyang Lake Environment and Resource Utilization, Ministry of Education, and Center for Algae Innovation & Engineering Research, School of Resources & Environment, Nanchang University, Nanchang 330031, China.
| | - Jingjing Li
- Key Laboratory of Poyang Lake Environment and Resource Utilization, Ministry of Education, and Center for Algae Innovation & Engineering Research, School of Resources & Environment, Nanchang University, Nanchang 330031, China.
| | - Rui Xu
- Jiangxi Ganneng Co., Ltd, Nanchang 330096, China.
| | - Jin Liu
- Key Laboratory of Poyang Lake Environment and Resource Utilization, Ministry of Education, and Center for Algae Innovation & Engineering Research, School of Resources & Environment, Nanchang University, Nanchang 330031, China.
| | - Wenguang Zhou
- Key Laboratory of Poyang Lake Environment and Resource Utilization, Ministry of Education, and Center for Algae Innovation & Engineering Research, School of Resources & Environment, Nanchang University, Nanchang 330031, China.
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3
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Hong J, Sobhi M, Zheng H, Hu X, Cui Y, Yu Z, Xu X, Zhu F, Huo S. Effective removing of rotifer contamination in microalgal lab-scale raceway ponds by light-induced phototaxis coupled with high-voltage pulse electroshock. BIORESOURCE TECHNOLOGY 2024; 394:130241. [PMID: 38142911 DOI: 10.1016/j.biortech.2023.130241] [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: 11/23/2023] [Revised: 12/19/2023] [Accepted: 12/20/2023] [Indexed: 12/26/2023]
Abstract
Rotifer reproduction control in open microalgae cultivation systems poses a significant challenge for large-scale industries. Conventional methods, such as electric, meshing, and chemical techniques, are often expensive, ineffective, and may have adverse environmental-health impacts. This study investigated a promising control technique through light-induced phototaxis to concentrate rotifers in a specific spot, where they were electroshocked by local-limited exposure dose. The results showed that the rotifers had the most pronounced positive and negative phototropism with phototaxis rates of 66.7 % and -78.8 %, respectively, at blue-light irradiation of 30 µmol∙m-2∙s-1 and red-light irradiation of 22.5 µmol∙m-2∙s-1 for 20 min. The most effective electroshock configuration employed 1200 V/cm for 15 min with a 1-second cycle time and a 10 % duty cycle, resulting in a 75.0 % rotifer removal rate without impacting microalgae growth. The combination of the two light beams could effectively lead rotifers to designated areas where they were electrocuted successfully.
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Affiliation(s)
- Ji Hong
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Mostafa Sobhi
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China; Agricultural and Bio-systems Engineering Department, Faculty of Agriculture, Alexandria University, Alexandria, Egypt
| | - HongJing Zheng
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Xinjuan Hu
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Yi Cui
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Zhen Yu
- School of Grain Science and Technology, Jiangsu University of Science and Technology, Zhenjiang 212013, China
| | - Xiangru Xu
- School of Agricultural Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Feifei Zhu
- School of Life Sciences, Jiangsu University, Zhenjiang 212013, China
| | - Shuhao Huo
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China.
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4
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Algae processing by plasma discharge technology: A review. ALGAL RES 2023. [DOI: 10.1016/j.algal.2023.102983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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5
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Gao S, Zhou L, Yang W, Wang L, Liu X, Gong Y, Hu Q, Wang G. Overexpression of a novel gene (Pt2015) endows the commercial diatom Phaeodactylum tricornutum high lipid content and grazing resistance. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2022; 15:131. [PMID: 36435813 PMCID: PMC9701398 DOI: 10.1186/s13068-022-02221-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 11/04/2022] [Indexed: 06/16/2023]
Abstract
BACKGROUND The marine diatom Phaeodactylum tricornutum is a commercially viable species due to its bioactive substances and lipid productivity. Increasing attention has been paid to the isolation or genetic modification of species or strains with a rapid growth rate and large quantities of lipids. Furthermore, contamination of microzooplankton has been one of the major constraints in P. tricornutum large-scale cultivation, which adversely affects growth and greatly impedes the course of biomass production industrialization. RESULTS Here, based on our previous transcriptomics of P. tricornutum, we found a novel gene (ID: 7202015, hereafter called Pt2015) which affects morphotype of P. tricornutum. Pt2015 protein is located in the plastid, which is highly homologous to part of the sequences of exosome component. The morphotype of the Pt2015 knockout strain (termed 2015KO) using CRISPR/Cas9 method is fusiform, but the Pt2015 overexpression strain (termed oeT) demonstrates a majority triradiate morphotype (approximately 95%) which is stable and has been cultured for more than 200 generations. In addition, the oeT strain demonstrated a similar growth rate to the WT and simultaneously accumulated larger lipids droplets that increased by approximately 30% compared to that of the WT. More importantly, the grazing rate of the amoebae cultured in the oeT strain significantly decreased in comparison with that cultured in WT, suggesting that the oeT can effectively avoid being eaten by microzooplankton. CONCLUSIONS Therefore, the oeT strain not only improves our understanding of morphotype conversion in diatoms but also demonstrates potential applications for large-scale cultivation of P. tricornutum.
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Affiliation(s)
- Shan Gao
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Center for Ocean Mega‑Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Lu Zhou
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Center for Ocean Mega‑Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
- College of Earth Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Wenting Yang
- College of Life Science, Qingdao Agricultural University, Qingdao, China
| | - Lijun Wang
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Center for Ocean Mega‑Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Xuehua Liu
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Center for Ocean Mega‑Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Yingchun Gong
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - Qiang Hu
- CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
- Faculty of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Guangce Wang
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Center for Ocean Mega‑Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.
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6
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Raja K, Kadirvel V, Subramaniyan T. Seaweeds, an aquatic plant-based protein for sustainable nutrition- a review. FUTURE FOODS 2022. [DOI: 10.1016/j.fufo.2022.100142] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
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7
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Molina-Grima E, García-Camacho F, Acién-Fernández FG, Sánchez-Mirón A, Plouviez M, Shene C, Chisti Y. Pathogens and predators impacting commercial production of microalgae and cyanobacteria. Biotechnol Adv 2021; 55:107884. [PMID: 34896169 DOI: 10.1016/j.biotechadv.2021.107884] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 11/25/2021] [Accepted: 12/02/2021] [Indexed: 02/09/2023]
Abstract
Production of phytoplankton (microalgae and cyanobacteria) in commercial raceway ponds and other systems is adversely impacted by phytoplankton pathogens, including bacteria, fungi and viruses. In addition, cultures are susceptible to productivity loss, or crash, through grazing by contaminating zooplankton such as protozoa, rotifers and copepods. Productivity loss and product contamination are also caused by otherwise innocuous invading phytoplankton that consume resources in competition with the species being cultured. This review is focused on phytoplankton competitors, pathogens and grazers of significance in commercial culture of microalgae and cyanobacteria. Detection and identification of these biological contaminants are discussed. Operational protocols for minimizing contamination, and methods of managing it, are discussed.
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Affiliation(s)
- Emilio Molina-Grima
- Department of Chemical Engineering, University of Almería, 04120 Almería, Spain
| | | | | | | | - Maxence Plouviez
- School of Food and Advanced Technology, Massey University, Private Bag 11 222, Palmerston North, New Zealand
| | - Carolina Shene
- Center for Biotechnology and Bioengineering (CeBiB), Center of Food Biotechnology and Bioseparations, BIOREN and Department of Chemical Engineering, Universidad de La Frontera, Francisco Salazar 01145, Temuco 4780000, Chile
| | - Yusuf Chisti
- School of Engineering, Massey University, Private Bag 11 222, Palmerston North, New Zealand.
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8
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From biorefinery of microalgal biomass to vacuum impregnation of fruit. A multidisciplinary strategy to develop innovative food with increased nutritional properties. INNOV FOOD SCI EMERG 2021. [DOI: 10.1016/j.ifset.2021.102677] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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9
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Pulse Electric Field Technology for Wastewater and Biomass Residues’ Improved Valorization. Processes (Basel) 2021. [DOI: 10.3390/pr9050736] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Development and adoption of more efficient and robust technologies for reuse of wastewater embedded resources, in particular materials and energy, is becoming an unavoidable necessity. Among many emerging technologies in the sector of wastewater treatment residuals valorization, Pulsed Electric Field (PEF) processes have shown interesting potential, although they have not yet entered the sector’s mainstream as a consolidated commercial technology, as in other industrial applications, such as the food, medical, and bio-based industries. PEF is a non-thermal technology suitable to biological applications, involving gentle cell disintegration and enhanced cell membrane permeability and as such applicable to disinfection, sterilization, and to those processes that benefit from an enhanced extraction of organic compounds from biological matter, such as anaerobic digestion, biological processes for recovery of nutrients, and biorefinery of cell-embedded compounds. PEF technology applications in wastewater/biomass residues management are reported and advantages, drawbacks, and barriers of the technology are discussed in this paper.
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10
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Zhu Z, Jiang J, Fa Y. Overcoming the Biological Contamination in Microalgae and Cyanobacteria Mass Cultivations for Photosynthetic Biofuel Production. Molecules 2020; 25:molecules25225220. [PMID: 33182530 PMCID: PMC7698126 DOI: 10.3390/molecules25225220] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 11/06/2020] [Accepted: 11/09/2020] [Indexed: 02/08/2023] Open
Abstract
Microalgae and cyanobacteria have shown significant potential for the development of the next biofuels innovation because of their own characteristics as photosynthetic microorganisms. However, it is confronted with a lot of severe challenges on the economic scaling-up of the microalgae- and cyanobacteria-based biofuels production. One of these major challenges is the lack of a reliable preventing and controlling culture system of biological contamination, which can attack the cell growth or product accumulation causing crashing effects. To increase the commercial viability of microalgae- and cyanobacteria-based biofuels production, overcoming the biological contaminations should be at the top of the priority list. Here, we highlight the importance of two categories of biological contaminations and their controlling strategies in the mass cultivations of microalgae and cyanobacteria, and outline the directions that should be exploited in the future.
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Affiliation(s)
- Zhi Zhu
- The Key Laboratory of Biotechnology for Medicinal Plants of Jiangsu Province and School of Life Science, Jiangsu Normal University, Xuzhou 221116, China;
| | - Jihong Jiang
- The Key Laboratory of Biotechnology for Medicinal Plants of Jiangsu Province and School of Life Science, Jiangsu Normal University, Xuzhou 221116, China;
- Correspondence: (J.J.); (Y.F.)
| | - Yun Fa
- CAS Key Laboratory of Bio-Based Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China
- Correspondence: (J.J.); (Y.F.)
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11
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Han J, Thomsen L, Pan K, Wang P, Wawilow T, Osundeko O, Wang S, Theilen U, Thomsen C. Treating wastewater by indigenous microalgae strain in pilot platform located inside a municipal wastewater treatment plant. ENVIRONMENTAL TECHNOLOGY 2020; 41:3261-3271. [PMID: 30961473 DOI: 10.1080/09593330.2019.1604816] [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: 01/29/2019] [Accepted: 04/02/2019] [Indexed: 06/09/2023]
Abstract
Various resources from a municipal wastewater treatment plant (MWTP) are available for microalgae cultivation plants, suggesting that a combination of these technologies can be used to produce microalgae biomass and remove contaminants at a low cost. In this study, the growth performance and nutrient removal efficiency of an indigenous Scenedesmus sp. in various wastewater media with different exchange patterns were investigated firstly, then transferred to a pilot-scale photobioreactor (located inside a MWTP) for bioremediation use. The temperature and pH of the platform were maintained at 15-30°C and 7.6, respectively. The N H 4 + - N , N O 3 - - N , and P O 4 3 - - P of the wastewater could be reduced to below 0.05, 0.40, and 0.175 mg L-1, respectively. Our results indicate that microalgae cultivation using the resources of a MWTP can achieve high algal biomass productivity and nutrient removal rate. Our study also suggests that efficient technology for controlling zooplankton needs to be developed.
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Affiliation(s)
- Jichang Han
- Department of Physics and Earth Sciences, Jacobs University of Bremen, Bremen, Germany
- College of Marine Life Science, Ocean University of China, Qingdao, People's Republic of China
| | - Laurenz Thomsen
- Department of Physics and Earth Sciences, Jacobs University of Bremen, Bremen, Germany
| | - Kehou Pan
- Function Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, People's Republic of China
- Ministry of Education, Key Laboratory of Mariculture (Ocean University of China), Qingdao, People's Republic of China
| | - Pu Wang
- Laboratory of protozoology, Ocean University of China, Qingdao, People's Republic of China
| | - Tatjana Wawilow
- Competence Centre for Energy and Environmental Engineering, THM Technische Hochschule Mittelhessen University of Applied Sciences, Giessen, Germany
| | - Olumayowa Osundeko
- Department of Physics and Earth Sciences, Jacobs University of Bremen, Bremen, Germany
| | - Song Wang
- Department of Physics and Earth Sciences, Jacobs University of Bremen, Bremen, Germany
| | - Ulf Theilen
- Competence Centre for Energy and Environmental Engineering, THM Technische Hochschule Mittelhessen University of Applied Sciences, Giessen, Germany
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Techniques to Control Microbial Contaminants in Nonsterile Microalgae Cultivation. Appl Biochem Biotechnol 2020; 192:1376-1385. [PMID: 32809108 PMCID: PMC8553695 DOI: 10.1007/s12010-020-03414-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 08/12/2020] [Indexed: 11/18/2022]
Abstract
The aim of this mini-review with own results was an identification of techniques to suppress the growth of microbial contaminants under photo- and mixotrophic conditions. Techniques identified are the modification of environmental conditions, such as pH, oxygen, and nutrient concentrations, as well as the application of pulsed electric field, ultrasonication, and surfactants. In phototrophic cultivations, the mentioned techniques result in a decrease of number of predatory cells, but not in a complete removal. Measures to suppress the growth of contaminations (e.g., bacteria and fungi) in mixotrophic cultivations could not be identified. The co-cultivation of algae and fungi, however, was found to be beneficial for the utilization of unusual carbon compounds (e.g., phenolic compounds).
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13
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Gateau H, Blanckaert V, Veidl B, Burlet-Schiltz O, Pichereaux C, Gargaros A, Marchand J, Schoefs B. Application of pulsed electric fields for the biocompatible extraction of proteins from the microalga Haematococcus pluvialis. Bioelectrochemistry 2020; 137:107588. [PMID: 33147566 DOI: 10.1016/j.bioelechem.2020.107588] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2019] [Revised: 06/23/2020] [Accepted: 06/25/2020] [Indexed: 12/19/2022]
Abstract
This study aims to employ a pulsed electric field (PEF) treatment for the biocompatible (non-destructive) extraction of proteins from living cells of the green microalga Haematococcus pluvialis. Using a field strength of 1 kV cm-1, we achieved the extraction of 10.2 µg protein per mL of culture, which corresponded to 46% of the total amount of proteins that could be extracted by complete destructive extraction (i.e. the grinding of biomass with glass beads). We found that the extraction yield was not improved by stronger field strengths and was not dependent on the pulse frequency. A biocompatibility index (BI) was defined as the relative abundance of cells that remained alive after the PEF treatment. This index relied on measurements of several physiological parameters after a PEF treatment. It was found that at 1 kV cm-1 that cultures recovered after 72 h. Therefore, these PEF conditions constituted a good compromise between protein extraction efficiency and culture survival. To characterize the PEF treatment further at a molecular level, mass spectrometry-based proteomics analyses of PEF-prepared extracts was used. This led to the identification of 52 electro-extracted proteins. Of these, only 16 proteins were identified when proteins were extracted with PEF at 0.5 cm-1. They belong to core metabolism, stress response and cell movement. Unassigned proteins were also extracted. Their physiological implications and possible utilization in food as alimentary complements are discussed.
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Affiliation(s)
- Hélène Gateau
- Metabolism, Bioengineering of Molecules from Microalgae and Applications (MIMMA), Mer Molécules Santé, IUML - FR 3473 CNRS, Le Mans University, Le Mans, France
| | - Vincent Blanckaert
- Metabolism, Bioengineering of Molecules from Microalgae and Applications (MIMMA), Mer Molécules Santé, IUML - FR 3473 CNRS, IUT de Laval, Le Mans University, Le Mans, France
| | - Brigitte Veidl
- Metabolism, Bioengineering of Molecules from Microalgae and Applications (MIMMA), Mer Molécules Santé, IUML - FR 3473 CNRS, Le Mans University, Le Mans, France
| | - Odile Burlet-Schiltz
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse UPS, CNRS, Toulouse, France
| | - Carole Pichereaux
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse UPS, CNRS, Toulouse, France; Fédération de Recherche (FR3450), Agrobiosciences, Interactions et Biodiversité (FRAIB), CNRS, Toulouse, France
| | | | - Justine Marchand
- Metabolism, Bioengineering of Molecules from Microalgae and Applications (MIMMA), Mer Molécules Santé, IUML - FR 3473 CNRS, Le Mans University, Le Mans, France
| | - Benoît Schoefs
- Metabolism, Bioengineering of Molecules from Microalgae and Applications (MIMMA), Mer Molécules Santé, IUML - FR 3473 CNRS, Le Mans University, Le Mans, France.
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14
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Eleršek T, Flisar K, Likozar B, Klemenčič M, Golob J, Kotnik T, Miklavčič D. Electroporation as a Solvent-Free Green Technique for Non-Destructive Extraction of Proteins and Lipids From Chlorella vulgaris. Front Bioeng Biotechnol 2020; 8:443. [PMID: 32478057 PMCID: PMC7237570 DOI: 10.3389/fbioe.2020.00443] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Accepted: 04/17/2020] [Indexed: 02/02/2023] Open
Abstract
Proteins extracted from microalgae for food, personal care products and cosmetics must be of high purity, requiring solvent-free extraction techniques despite their generally considerably lower protein yield and higher energy consumption. Here, three such approaches for green extraction of proteins from Chlorella vulgaris were evaluated: ultrasound, freeze-thawing, and electroporation; chemical lysis was used as positive control (maximal achievable extraction), and no extraction treatment as negative control. Compared to chemical lysis, electroporation yielded the highest fraction of extracted protein mass in the supernatant (≤27%), ultrasound ≤24%, and freeze-thawing ≤15%. After a growth lag of several days, electroporated groups of algal cells started to exhibit growth dynamics similar to the negative control group, while no growth regeneration was detected in groups exposed to ultrasound, freeze-thawing, or chemical lysis. For electroporation as the most efficient and the only non-destructive among the considered solvent-free protein extraction techniques, simultaneous extraction of intracellular algal lipids into supernatant was then investigated by HPLC, proving relatively low-yield (≤7% of the total algal lipid mass), yet feasible for glycerides (tri-, di-, and mono-) as well as other fatty acid derivatives. Our results show that electroporation, though lower in extraction yields than chemical lysis or mechanical disintegration, is in contrast to them a technique for largely debris-free extraction of proteins from microalgae, with no need for prior concentration or drying, with feasible growth regeneration, and with potential for simultaneous extraction of intracellular algal lipids into the supernatant.
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Affiliation(s)
- Tina Eleršek
- Department of Genetic Toxicology and Cancer Biology, National Institute of Biology, Ljubljana, Slovenia
| | - Karel Flisar
- Faculty of Electrical Engineering, University of Ljubljana, Ljubljana, Slovenia
| | - Blaž Likozar
- National Institute of Chemistry, Ljubljana, Slovenia
| | - Marina Klemenčič
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia
| | - Janvit Golob
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia
| | - Tadej Kotnik
- Faculty of Electrical Engineering, University of Ljubljana, Ljubljana, Slovenia
| | - Damijan Miklavčič
- Faculty of Electrical Engineering, University of Ljubljana, Ljubljana, Slovenia
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Leonhardt L, Käferböck A, Smetana S, de Vos R, Toepfl S, Parniakov O. Bio-refinery of Chlorella sorokiniana with pulsed electric field pre-treatment. BIORESOURCE TECHNOLOGY 2020; 301:122743. [PMID: 31945684 DOI: 10.1016/j.biortech.2020.122743] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2019] [Revised: 12/31/2019] [Accepted: 01/02/2020] [Indexed: 06/10/2023]
Abstract
The aim of this work was to investigate the potential of PEF technology for green extraction of microalgal pigments and lipids from fresh Chlorella sorokiniana suspensions. Efficiencies of PEF treatment and different solvent systems application to C.sorokiniana were compared to efficiencies of untreated biomass extraction. Differences in chlorophyll extraction of untreated and PEF treated C.sorokiniana were only seen at short extraction times. Beneficial PEF-effect was minimised for long-time extractions of larger algae quantities where yields aligned. Extraction attempts on C. sorokiniana lipids did not show increased extractability after PEF treatment, which underlined the statement of PEF representing a rather ineffective disruption method for microalgae holding rigid cell walls.
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Affiliation(s)
- Lars Leonhardt
- German Institute of Food Technologies (DIL e.V.), Quakenbrück, Germany
| | - Anna Käferböck
- Elea Vertriebs- und Vermarktungsgesellschaft mbH, Prof. von Klitzing Str. 9, 49610 Quakenbrück, Germany; University of Applied Sciences Upper Austria, Faculty of Engineering, Department Food technology and Nutrition, Stelzhamerstraße 23, 4600 Wels, Austria
| | - Sergiy Smetana
- German Institute of Food Technologies (DIL e.V.), Quakenbrück, Germany.
| | - Ronald de Vos
- Algae Holland B.V, Lechstraat 5, 6674 AV Herveld, Netherlands
| | - Stefan Toepfl
- Elea Vertriebs- und Vermarktungsgesellschaft mbH, Prof. von Klitzing Str. 9, 49610 Quakenbrück, Germany
| | - Oleksii Parniakov
- Elea Vertriebs- und Vermarktungsgesellschaft mbH, Prof. von Klitzing Str. 9, 49610 Quakenbrück, Germany
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16
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Mamo G, Mattiasson B. Alkaliphiles: The Versatile Tools in Biotechnology. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2020; 172:1-51. [PMID: 32342125 DOI: 10.1007/10_2020_126] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The extreme environments within the biosphere are inhabited by organisms known as extremophiles. Lately, these organisms are attracting a great deal of interest from researchers and industrialists. The motive behind this attraction is mainly related to the desire for new and efficient products of biotechnological importance and human curiosity of understanding nature. Organisms living in common "human-friendly" environments have served humanity for a very long time, and this has led to exhaustion of the low-hanging "fruits," a phenomenon witnessed by the diminishing rate of new discoveries. For example, acquiring novel products such as drugs from the traditional sources has become difficult and expensive. Such challenges together with the basic research interest have brought the exploration of previously neglected or unknown groups of organisms. Extremophiles are among these groups which have been brought to focus and garnering a growing importance in biotechnology. In the last few decades, numerous extremophiles and their products have got their ways into industrial, agricultural, environmental, pharmaceutical, and other biotechnological applications.Alkaliphiles, organisms which thrive optimally at or above pH 9, are one of the most important classes of extremophiles. To flourish in their extreme habitats, alkaliphiles evolved impressive structural and functional adaptations. The high pH adaptation gave unique biocatalysts that are operationally stable at elevated pH and several other novel products with immense biotechnological application potential. Advances in the cultivation techniques, success in gene cloning and expression, metabolic engineering, metagenomics, and other related techniques are significantly contributing to expand the application horizon of these remarkable organisms of the 'bizarre' world. Studies have shown the enormous potential of alkaliphiles in numerous biotechnological applications. Although it seems just the beginning, some fantastic strides are already made in tapping this potential. This work tries to review some of the prominent applications of alkaliphiles by focusing such as on their enzymes, metabolites, exopolysaccharides, and biosurfactants. Moreover, the chapter strives to assesses the whole-cell applications of alkaliphiles including in biomining, food and feed supplementation, bioconstruction, microbial fuel cell, biofuel production, and bioremediation.
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Affiliation(s)
| | - Bo Mattiasson
- Department of Biotechnology, Lund University, Lund, Sweden
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17
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Biological contamination and its chemical control in microalgal mass cultures. Appl Microbiol Biotechnol 2019; 103:9345-9358. [PMID: 31720774 DOI: 10.1007/s00253-019-10193-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 09/29/2019] [Accepted: 10/07/2019] [Indexed: 12/18/2022]
Abstract
Microalgae are versatile sources of bioproducts, a solution for many environmental problems. However, and despite its importance, one of the main problems in large-scale cultures-the presence of contaminants-is rarely systematically approached. Contamination, or the presence of undesirable organisms in a culture, is deleterious for the culture and frequently leads to culture crashes. To avoid contamination, closed systems can be used; however, for very large-scale open systems, contamination is unavoidable and remediation procedures are necessary-ranging from physicochemical treatment to addition of biocidal substances. In all cases, early detection and culture monitoring are paramount. This article describes the biological contaminants, contamination mechanisms, and control systems used in open and closed cultures, discussing the latest advances and techniques in the area. It also discusses the complex interactions of algae with other microorganisms that can be expected in cultivation systems.
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18
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Buchmann L, Mathys A. Perspective on Pulsed Electric Field Treatment in the Bio-based Industry. Front Bioeng Biotechnol 2019; 7:265. [PMID: 31681745 PMCID: PMC6805697 DOI: 10.3389/fbioe.2019.00265] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Accepted: 09/27/2019] [Indexed: 12/21/2022] Open
Abstract
The bio-based industry is urged to find solutions to meet the demands of a growing world population. In this context, increased resource efficiency is a major goal. Pulsed electric field (PEF) processing is a promising technological solution. Conventional PEF and the emerging area of nanosecond PEF (nsPEF) have been shown to induce various biological effects, with nsPEF inducing pronounced intracellular effects, which could provide solutions for currently faced challenges. Based on the flexibility and continuous operation of PEF and nsPEF processing, the technology can be integrated into many existing cultivation systems; its modularity provides an approach for inducing specific effects. Depending on the treatment conditions, selective inactivation, continuous extraction without impeding cell viability, as well as the stimulation of cell growth and/or cellular compound stimulation are potential applications in the bio-based industry. However, continuous treatment currently involves heterogeneous energy inputs. Increasing the homogeneity of PEF and nsPEF processing by considering the flow and electric field heterogeneity may allow for more targeted effects on biological cells, further increasing the potential of the technology for bio-based applications. We provide an overview of existing and potential applications of PEF and nsPEF and suggest that theoretical and practical analyses of flow and electric field heterogeneity may provide a basis for obtaining more targeted effects on biological cells and for further increasing the bio-based applications of the technology, which thereby could become a key technology for circular economy approaches in the future.
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Affiliation(s)
- Leandro Buchmann
- Laboratory of Sustainable Food Processing, Department of Health Sciences and Technology, Institute of Food Nutrition and Health, IFNH, ETH Zurich, Zurich, Switzerland
| | - Alexander Mathys
- Laboratory of Sustainable Food Processing, Department of Health Sciences and Technology, Institute of Food Nutrition and Health, IFNH, ETH Zurich, Zurich, Switzerland
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Isolation and evaluation of a novel strain of Chlorella sorokiniana that resists grazing by the predator Poterioochromonas malhamensis. ALGAL RES 2019. [DOI: 10.1016/j.algal.2019.101429] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Wang Y, Gong Y, Dai L, Sommerfeld M, Zhang C, Hu Q. Identification of harmful protozoa in outdoor cultivation of Chlorella and the use of ultrasonication to control contamination. ALGAL RES 2018. [DOI: 10.1016/j.algal.2018.02.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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21
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Ma M, Yuan D, He Y, Park M, Gong Y, Hu Q. Effective control of Poterioochromonas malhamensis in pilot-scale culture of Chlorella sorokiniana GT-1 by maintaining CO2-mediated low culture pH. ALGAL RES 2017. [DOI: 10.1016/j.algal.2017.06.023] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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22
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Li C, Li J, Lan CQ, Liao D. Protozoa inhibition by different salts: Osmotic stress or ionic stress? Biotechnol Prog 2017; 33:1418-1424. [DOI: 10.1002/btpr.2510] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 06/02/2017] [Indexed: 11/11/2022]
Affiliation(s)
- Changhao Li
- Department of Chemical and Biological Engineering; University of Ottawa; 161 Louis Pasteur Private, Ottawa ON K1N 6N5 Canada
| | - Jingya Li
- Department of Chemical and Biological Engineering; University of Ottawa; 161 Louis Pasteur Private, Ottawa ON K1N 6N5 Canada
- Guangxi Key Laboratory of Petrochemical Resource Processing and Process Intensification Technology; School of Chemistry and Chemical Engineering, Guangxi University; Nanning 530004 China
| | - Christopher Q. Lan
- Guangxi Key Laboratory of Petrochemical Resource Processing and Process Intensification Technology; School of Chemistry and Chemical Engineering, Guangxi University; Nanning 530004 China
| | - Dankui Liao
- Department of Chemical and Biological Engineering; University of Ottawa; 161 Louis Pasteur Private, Ottawa ON K1N 6N5 Canada
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Zhu Z, Luan G, Tan X, Zhang H, Lu X. Rescuing ethanol photosynthetic production of cyanobacteria in non-sterilized outdoor cultivations with a bicarbonate-based pH-rising strategy. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:93. [PMID: 28416967 PMCID: PMC5391583 DOI: 10.1186/s13068-017-0765-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 03/18/2017] [Indexed: 06/07/2023]
Abstract
BACKGROUND Ethanol photosynthetic production based on cyanobacteria cell factories utilizing CO2 and solar energy provides an attractive solution for sustainable production of green fuels. However, the scaling up processes of cyanobacteria cell factories were usually threatened or even devastated by biocontaminations, which restricted biomass or products accumulations of cyanobacteria cells. Thus it is of great significance to develop reliable biocontamination-controlling strategies for promoting ethanol photosynthetic production in large scales. RESULTS The scaling up process of a previously developed Synechocystis strain Syn-HZ24 for ethanol synthesis was severely inhibited and devastated by a specific contaminant, Pannonibacter phragmitetus, which overcame the growths of cyanobacteria cells and completely consumed the ethanol accumulation in the cultivation systems. Physiological analysis revealed that growths and ethanol-consuming activities of the contaminant were sensitive to alkaline conditions, while ethanol-synthesizing cyanobacteria strain Syn-HZ24 could tolerate alkaline pH conditions as high as 11.0, indicating that pH-increasing strategy might be a feasible approach for rescuing ethanol photosynthetic production in outdoor cultivation systems. Thus, we designed and evaluated a Bicarbonate-based Integrated Carbon Capture System (BICCS) derived pH-rising strategy to rescue the ethanol photosynthetic production in non-sterilized conditions. In lab scale artificially simulated systems, pH values of BG11 culture medium were maintained around 11.0 by 180 mM NaHCO3 and air steam, under which the infection of Pannonibacter phragmitetus was significantly restricted, recovering ethanol production of Syn-HZ24 by about 80%. As for outdoor cultivations, ethanol photosynthetic production of Syn-HZ24 was also successfully rescued by the BICCS-derived pH-rising strategy, obtaining a final ethanol concentration of 0.9 g/L after 10 days cultivation. CONCLUSIONS In this work, a novel product-consuming biocontamination pattern in cyanobacteria cultivations, causing devastated ethanol photosynthetic production, was identified and characterized. Physiological analysis of the essential ethanol-consuming contaminant directed the design and application of a pH-rising strategy, which effectively and selectively controlled the contamination and rescued ethanol photosynthetic production. Our work demonstrated the importance of reliable contamination control systems and strategies for large scale outdoor cultivations of cyanobacteria, and provided an inspiring paradigm for targeting effective solutions.
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Affiliation(s)
- Zhi Zhu
- Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao, 266101 China
- Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao, 266101 China
- University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Guodong Luan
- Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao, 266101 China
- Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao, 266101 China
| | - Xiaoming Tan
- Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao, 266101 China
- Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao, 266101 China
| | - Haocui Zhang
- Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao, 266101 China
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072 China
| | - Xuefeng Lu
- Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao, 266101 China
- Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao, 266101 China
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Flynn KJ, Kenny P, Mitra A. Minimising losses to predation during microalgae cultivation. JOURNAL OF APPLIED PHYCOLOGY 2017; 29:1829-1840. [PMID: 28775656 PMCID: PMC5514209 DOI: 10.1007/s10811-017-1112-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Revised: 02/22/2017] [Accepted: 02/23/2017] [Indexed: 05/07/2023]
Abstract
We explore approaches to minimise impacts of zooplanktonic pests upon commercial microalgal crops using system dynamics models to describe algal growth controlled by light and nutrient availability and zooplankton growth controlled by crop abundance and nutritional quality. Losses of microalgal crops are minimised when their growth is fastest and, in contrast, also when growing slowly under conditions of nutrient exhaustion. In many culture systems, however, dwindling light availability due to self-shading in dense suspensions favours slow growth under nutrient sufficiency. Such a situation improves microalgal quality as prey, enhancing zooplankton growth, and leads to rapid crop collapse. Timing of pest entry is important; crop losses are least likely in established, nutrient-exhausted microalgal communities grown for high C-content (e.g. for biofuels). A potentially useful approach is to promote a low level of P-stress that does not adversely affect microalgal growth but which produces a crop that is suboptimal for zooplankton growth.
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Straessner R, Silve A, Eing C, Rocke S, Wuestner R, Leber K, Mueller G, Frey W. Microalgae precipitation in treatment chambers during pulsed electric field (PEF) processing. INNOV FOOD SCI EMERG 2016. [DOI: 10.1016/j.ifset.2016.07.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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Ganuza E, Sellers CE, Bennett BW, Lyons EM, Carney LT. A Novel Treatment Protects Chlorella at Commercial Scale from the Predatory Bacterium Vampirovibrio chlorellavorus. Front Microbiol 2016; 7:848. [PMID: 27379027 PMCID: PMC4913114 DOI: 10.3389/fmicb.2016.00848] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 05/22/2016] [Indexed: 11/13/2022] Open
Abstract
The predatory bacterium, Vampirovibrio chlorellavorus, can destroy a Chlorella culture in just a few days, rendering an otherwise robust algal crop into a discolored suspension of empty cell walls. Chlorella is used as a benchmark for open pond cultivation due to its fast growth. In nature, V. chlorellavorus plays an ecological role by controlling this widespread terrestrial and freshwater microalga, but it can have a devastating effect when it attacks large commercial ponds. We discovered that V. chlorellavorus was associated with the collapse of four pilot commercial-scale (130,000 L volume) open-pond reactors. Routine microscopy revealed the distinctive pattern of V. chlorellavorus attachment to the algal cells, followed by algal cell clumping, culture discoloration and ultimately, growth decline. The “crash” of the algal culture coincided with increasing proportions of 16s rRNA sequencing reads assigned to V. chlorellavorus. We designed a qPCR assay to predict an impending culture crash and developed a novel treatment to control the bacterium. We found that (1) Chlorella growth was not affected by a 15 min exposure to pH 3.5 in the presence of 0.5 g/L acetate, when titrated with hydrochloric acid and (2) this treatment had a bactericidal effect on the culture (2-log decrease in aerobic counts). Therefore, when qPCR results indicated a rise in V. chlorellavorus amplicons, we found that the pH-shock treatment prevented the culture crash and doubled the productive longevity of the culture. Furthermore, the treatment could be repeatedly applied to the same culture, at the beginning of at least two sequential batch cycles. In this case, the treatment was applied preventively, further increasing the longevity of the open pond culture. In summary, the treatment reversed the infection of V. chlorellavorus as confirmed by observations of bacterial attachment to Chlorella cells and by detection of V. chlorellavorus by 16s rRNA sequencing and qPCR assay. The pH-shock treatment is highly selective against prokaryotes, and it is a cost-effective treatment that can be used throughout the scale up and production process. To our knowledge, the treatment described here is the first effective control of V. chlorellavorus and will be an important tool for the microalgal industry and biofuel research.
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Affiliation(s)
- Eneko Ganuza
- Microbiology Group, Heliae Development LLC, Gilbert, AZ, USA
| | | | - Braden W Bennett
- Molecular Ecology Group, Heliae Development LLC, Gilbert, AZ, USA
| | - Eric M Lyons
- Microbiology Group, Heliae Development LLC, Gilbert, AZ, USA
| | - Laura T Carney
- Molecular Ecology Group, Heliae Development LLC, Gilbert, AZ, USA
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Touloupakis E, Cicchi B, Benavides AMS, Torzillo G. Effect of high pH on growth of Synechocystis sp. PCC 6803 cultures and their contamination by golden algae (Poterioochromonas sp.). Appl Microbiol Biotechnol 2015; 100:1333-1341. [PMID: 26541331 PMCID: PMC4717179 DOI: 10.1007/s00253-015-7024-0] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 08/31/2015] [Accepted: 09/08/2015] [Indexed: 11/29/2022]
Abstract
Culturing cyanobacteria in a highly alkaline environment is a possible strategy for controlling contamination by other organisms. Synechocystis PCC 6803 cells were grown in continuous cultures to assess their growth performance at different pH values. Light conversion efficiency linearly decreased with the increase in pH and ranged between 12.5 % (PAR) at pH 7.5 (optimal) and decreased to 8.9 % at pH 11.0. Photosynthetic activity, assessed by measuring both chlorophyll fluorescence and photosynthesis rate, was not much affected going from pH 7.5 to 11.0, while productivity, growth yield, and biomass yield on light energy declined by 32, 28, and 26 % respectively at pH 11.0. Biochemical composition of the biomass did not change much within pH 7 and 10, while when grown at pH 11.0, carbohydrate content increased by 33 % while lipid content decreased by about the same amount. Protein content remained almost constant (average 65.8 % of dry weight). Cultures maintained at pH above 11.0 could grow free of contaminants (protozoa and other competing microalgae belonging to the species of Poterioochromonas).
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Affiliation(s)
- Eleftherios Touloupakis
- Istituto per lo Studio degli Ecosistemi, CNR, Via Madonna del Piano 10, I-50019, Sesto Fiorentino, Italy
| | - Bernardo Cicchi
- Istituto per lo Studio degli Ecosistemi, CNR, Via Madonna del Piano 10, I-50019, Sesto Fiorentino, Italy
| | - Ana Margarita Silva Benavides
- Escuela de Biología, Universidad de Costa Rica, San Pedro, San José, 2060, Costa Rica
- Centro de Investigación en Ciencias del Mar y Limnología (CIMAR), Universidad de Costa Rica, San Pedro, San José, 2060, Costa Rica
| | - Giuseppe Torzillo
- Istituto per lo Studio degli Ecosistemi, CNR, Via Madonna del Piano 10, I-50019, Sesto Fiorentino, Italy.
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