Browsing by Author "Kao, Chien-Ya"

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A mutant strain of microalga Chlorella sp for the carbon dioxide capture from biogas
(2012-01-01)
Kao, Chien-Ya
;
Chiu, Sheng-Yi
;
Huang, Tzu-Ting
;
Dai, Le
;
Wang, Guan-Hua
To upgrade biogas produced from the anaerobic digestion of swine wastewater, an outdoor photobioreactor was established in this study. A mutant strain of microalga Chlorella sp. MM-2 was firstly isolated by ethyl methane sulfonate-induced random mutagenesis. The Chlorella sp. MM-2 grew in the presence of gas containing H2S < 100 ppm, and the growth capacity of the microalgal culture aerated with 80% CH, was similar to 70% that of the control culture (0% CH4). In the field study, CO2 capture efficiency of the Chlorella cultures, at a biomass concentration of 1.2 g L-1, from the desulfurized biogas (-20% CO2, 70% CH4 and H2S < 100 ppm) was approximate 70% on cloudy days and 80% on sunny days. CH4 concentration in the effluent biogas from the Chlorella cultures was increased to approximate 84% on cloudy days and 87% on sunny days from its original 70%. The established outdoor photobioreactor system using a gas cycle-switching operation could be used as a CO2 capture model for biogas upgrading. Crown Copyright (C) 2011 Published by Elsevier Ltd. All rights reserved.
Ability of a mutant strain of the microalga Chlorella sp to capture carbon dioxide for biogas upgrading
(2012-05-01)
Kao, Chien-Ya
;
Chiu, Sheng-Yi
;
Huang, Tzu-Ting
;
Dai, Le
;
Hsu, Ling-Kang
In this study, a culture system with outdoor microalgae-incorporating photobioreactors was utilized to upgrade biogas produced from the anaerobic digestion of swine wastewater. Using ethyl methane sulfonate (EMS) random mutagenesis, we isolated a mutant strain of microalga, Chlorella sp. MB-9, which was tolerant to high CH4 and CO2. In the field study of outdoor operation, the maximum growth rates of Chlorella sp. MB-9 aerated with desulfurized biogas at 0.05, 0.1, 0.2 and 0.3 vvm were 0.32, 0.311, 0.275 and 0.251 g L-1 d(-1). In addition. similar to 70% of the CO2 in desulfurized biogas (similar to 20% CO2. similar to 70% CH4, and H2S < 50 ppm) could be captured by the Chlorella sp. MB-9 cultures. The CH4 concentration in the effluent biogas from the Chlorella cultures increased from its original 70% up to 85-90%. The established outdoor microalgae-incorporating culture system with a gas cycle-switching operation could be efficiently used as a CO2 capture model for biogas upgrading. (C) 2012 Elsevier Ltd. All rights reserved.
Characterization of the thermal-tolerant mutants of Chlorella sp with high growth rate and application in outdoor photobioreactor cultivation
(2010-04-01)
Ong, Seow-Chin
;
Kao, Chien-Ya
;
Chiu, Sheng-Yi
;
Tsai, Ming-Ta
;
Lin, Chih-Sheng
In this study, two thermal-tolerant mutants of Chlorella sp. MT-7 and MT-15, were isolated. In indoor cultivation, specific growth rate (mu, d(-1)) of the mutants were 1.4 to 1.8-fold at 25 degrees C and 3.3 to 6.7-fold at 40 C higher than those of wild type. The carbon dioxide fixation rate of both microalgal mutants was also significantly higher than that of wild type. In outdoor closed cultivation, where the temperature of culture broth was 41 +/- 1 degrees C, the mu of mutant strain MT-15 was 0.238 d(-1) during an 8-day cultivation. Whereas, the growth of wild type was inhibited in the outdoor cultivation. Our results show that the isolated microalgal strains are adaptable to be applied in outdoor cultivation in subtropical zones. (C) 2009 Elsevier Ltd. All rights reserved.
Cultivation of Chlorella sp GD using piggery wastewater for biomass and lipid production
(2015-10-01)
Kuo, Chiu-Mei
;
Chen, Tsai-Yu
;
Lin, Tsung-Hsien
;
Kao, Chien-Ya
;
Lai, Jinn-Tsyy
The development of a culture system for Chlorella sp. GD to efficiently produce biomass and oil for biodiesel production was investigated. Chlorella sp. GD was cultivated with 0%, 25%, 50%, 75% and 100% piggery wastewater (diluted by medium) at 300 mu mol m(-2) s(-1), a 2% CO2 aeration rate of 0.2 vvm and 26 +/- 1 degrees C; after a 10-day culture in batch cultures, the maximum specific growth rate and biomass productivity of the microalga obtained in 100% piggery wastewater were 0.839 d(-1) and 0.681 g L-1 d(-1), respectively. The highest lipid content and lipid productivity were 29.3% and 0.155 g L-1 d(-1) at 25% wastewater, respectively. In semi-continuous cultures, the biomass and lipid productivities with 25-75% wastewater ratios were greater than 0.852 and 0.128 g L-1 d(-1), respectively. These results show that Chlorella sp. GD grows efficiently in piggery wastewater, and that a stable growth performance was achieved for long-term microalgal cultivation in a semi-continuous culture. (C) 2015 Elsevier Ltd. All rights reserved.
Cultivation of microalgal Chlorella for biomass and lipid production using wastewater as nutrient resource
(2015-05-01)
Chiu, Sheng-Yi
;
Kao, Chien-Ya
;
Chen, Tsai-Yu
;
Chang, Yu-Bin
;
Kuo, Chiu-Mei
Using wastewater for microalgal cultures is beneficial for minimizing the use of freshwater, reducing the cost of nutrient addition, removing nitrogen and phosphorus from wastewater and producing microalgal biomass as bioresources for biofuel or high-value by-products. There are three main sources of wastewater, municipal (domestic), agricultural and industrial wastewater, which contain a variety of ingredients. Some components in the wastewater, such as nitrogen and phosphorus, are useful ingredients for microalgal cultures. In this review, the effects on the biomass and lipid production of microalgal Chlorella cultures using different kinds of wastewater were summarized. The use of the nutrients resource in wastewater for microalgal cultures was also reviewed. The effect of ammonium in wastewater on microalgal Chlorella growth was intensively discussed. In the end, limitations of wastewater-based of microalgal culture were commented in this review article. (C) 2014 Elsevier Ltd. All rights reserved.
Ferrofluid-assisted rapid and directional harvesting of marine microalgal Chlorella sp used for biodiesel production
(2017-11-01)
Ho, Shih-Hsin
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Chiu, Sheng-Yi
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Kao, Chien-Ya
;
Chen, Tsai-Yu
;
Chang, Yu-Bin
In this work, a novel harvesting strategy using ferrofluids coupled with flocculation as a magnetic directional harvesting system was developed, providing a fast and easy way to effectively collect microalgae with no further modifications made to the ferrofluids. With a ferrofluid dosage of 25 mg L-1, a high harvesting efficiency of 95-100% was achieved within 1 min. In addition, we successfully performed a wastewater recycling strategy coupled with a microalgal ferrofluid-harvesting dynamic flow-through system to harvest biomass of Chlorella sp. MTF-7 which could achieve over 80% of the maximum level after three repeated recycling cultivations. This work demonstrated the use of an integrated microalgal ferrofluid-harvesting dynamic flow-through system to develop a simple and effective strategy to enhance microalgal harvesting efficiency, along with wastewater recycling, in a marine microalgal Chlorella sp. MTF-7. (C) 2017 Elsevier Ltd. All rights reserved.
Lipid accumulation and CO(2) utilization of Nannochloropsis oculata in response to CO(2) aeration
(2009-01-01)
Chiu, Sheng-Yi
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Kao, Chien-Ya
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Tsai, Ming-Ta
;
Ong, Seow-Chin
;
Chen, Chiun-Hsun
In order to produce microalgal lipids that can be transformed to biodiesel fuel, effects of concentration of CO(2) aeration on the biomass production and lipid accumulation of Nannochloropsis oculata in a semicontinuous culture were investigated in this study. Lipid content of N. oculata cells at different growth phases was also explored. The results showed that the lipid accumulation from logarithmic phase to stationary phase of N. oculata NCTU-3 was significantly increased from 30.8% to 50.4%. In the microalgal cultures aerated with 2%, 5%, 10% and 15% CO(2), the maximal biomass and lipid productivity in the semicontinuous system were 0.480 and 0.142 g L(-1) d(-1) with 2% CO(2) aeration, respectively. Even the N. oculata NCTU-3 cultured in the semicontinuous system aerated with 15% CO(2), the biomass and lipid productivity could reach to 0.372 and 0.084 g L(-1) d(-1), respectively. In the comparison of productive efficiencies, the semicontinuous system was operated with two culture approaches over 12 d. The biomass and lipid productivity of N. oculata NCTU-3 were 0.497 and 0.151 g L(-1) d(-1) in one-day replacement (half broth was replaced each day), and were 0.296 and 0.121 g L(-1) d(-1) in three-day replacement (three fifth broth was replaced every 3 d), respectively. To optimize the condition for long-term biomass and lipid yield from N. oculata NCTU-3, this microalga was suggested to grow in the semicontinuous system aerated with 2% CO(2) and operated by one-day replacement. (C) 2008 Elsevier Ltd. All rights reserved.
Microalgal biomass production and on-site bioremediation of carbon dioxide, nitrogen oxide and sulfur dioxide from flue gas using Chlorella sp cultures
(2011-10-01)
Chiu, Sheng-Yi
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Kao, Chien-Ya
;
Huang, Tzu-Ting
;
Lin, Chia-Jung
;
Ong, Seow-Chin
The growth and on-site bioremediation potential of an isolated thermal- and CO(2)-tolerant mutant strain. Chlorella sp. MTF-7, were investigated. The Chlorella sp. MTF-7 cultures were directly aerated with the flue. gas generated from coke oven of a steel plant. The biomass concentration, growth rate and lipid content of Chlorella sp. MTF-7 cultured in an outdoor 50-L photobioreactor for 6 days was 2.87 g L(-1) (with an initial culture biomass concentration of 0.75 g L(-1)), 0.52 g L(-1) d(-1) and 25.2%, respectively. By the operation with intermittent flue gas aeration in a double-set photobioreactor system, average efficiency of CO(2) removal from the flue gas could reach to 60%, and NO and SO(2) removal efficiency was maintained at approximately 70% and 50%, respectively. Our results demonstrate that flue gas from coke oven could be directly introduced into Chlorella sp. MTF-7 cultures to potentially produce algal biomass and efficiently capture CO(2), NO and SO(2) from flue gas. (C) 2011 Elsevier Ltd. All rights reserved.
Reduction of CO2 by a high-density culture of Chlorella sp in a semicontinuous photobioreactor
(2008-06-01)
Chiu, Sheng-Yi
;
Kao, Chien-Ya
;
Chen, Chiun-Hsun
;
Kuan, Tang-Ching
;
Ong, Seow-Chin
The microalga incorporated photobioreactor is a highly efficient biological system for converting CO2 into biomass. Using microalgal photobioreactor as CO2 mitigation system is a practical approach for elimination of waste gas from the CO2 emission. In this study, the marine microalga, Chlorella sp. was cultured in a photobioreactor to assess biomass, lipid productivity and CO2 reduction. We also determined the effects of cell density and CO2 concentration on the growth of Chlorella sp. During an 8-day interval cultures in the semicontinuous cultivation, the specific growth rate and biomass of Chlorella sp. cultures in the conditions aerated 2-15% CO2 were 0.58-0.66 d(-1) and 0.76-0.87g L-1, respectively. At CO2 concentrations of 2%, 5%, 10% and 15%, the rate of CO2, reduction was 0.261, 0.316, 0.466 and 0.573 g h(-1), and efficiency of CO2 removal was 58%, 27%, 20% and 16%, respectively. The efficiency of CO2 removal was similar in the single photobioreactor and in the six-parallel photobioreactor. However, CO2 reduction, production of biomass, and production of lipid were six times greater in the six-parallel photobioreactor than those in the single photobioreactor. In conclusion, inhibition of microalgal growth cultured in the system with high CO2 (10-15%) aeration could be overcome via a high-density culture of microalgal inoculum that was adapted to 2% CO2. Moreover, biological reduction of CO2 in the established system could be parallely increased using the photo bioreactor consisting of multiple units. (c) 2007 Elsevier Ltd. All rights reserved.
The air-lift photobioreactors with flow patterning for high-density cultures of microalgae and carbon dioxide removal
(2009-06-01)
Chiu, Sheng-Yi
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Tsai, Ming-Ta
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Kao, Chien-Ya
;
Ong, Seow-Chin
;
Lin, Chih-Sheng
A photobioreactor containing microalgae is a highly efficient system for converting carbon dioxide (CO(2)) into biomass. Using a microalgal photobioreactor as a CO(2) mitigation system is a practical approach to the problem Of CO(2) emission from waste gas. In this study, a marine microalga, Chlorella sp. NCTU-2, was applied to assess biomass production and CO(2) removal. Three types of photobioreactors were designed and used: (i) without inner column (i.e. a bubble column), (ii) with a centric-tube column and (iii) with a porous centric-tube column. The specific growth rates (it) of the batch cultures in the bubble column, the centric-tube and the porous centric-tube photobioreactor were 0.180, 0.226 and 0.252 day(-1), respectively. The porous centric-tube photobioreactor, operated in semicontinuous culture mode with 10% CO(2) aeration, was evaluated. The results show that the maximum biomass productivity was 0.61 g/L when one fourth of the culture broth was recovered every 2 days. The CO(2) removal efficiency was also determined by measuring the influent and effluent loads at different aeration rates and cell densities of Chlorella sp. NCTU-2. The results show that the CO(2), removal efficiency was related to biomass concentration and aeration rate. The maximum CO(2) removal efficiency of the Chlorella sp. NCTU-2 culture was 63% when the biomass was maintained at 5.15 g/L concentration and 0.125 vvm aeration (volume gas per volume broth per min; 10% CO(2) in the aeration gas) in the porous centric-tube photobioreactor.
Utilization of carbon dioxide in industrial flue gases for the cultivation of microalga Chlorella sp.
(2014-08-01)
Kao, Chien-Ya
;
Chen, Tsai-Yu
;
Chang, Yu-Bin
;
Chiu, Tzai-Wen
;
Lin, Hsiun-Yu
The biomass and lipid productivity of Chlorella sp. MTF-15 cultivated using aeration with flue gases from a coke oven, hot stove or power plant in a steel plant of the China Steel Corporation in Taiwan were investigated. Using the flue gas from the coke oven, hot stove or power plant for cultivation, the microalgal strain obtained a maximum specific growth rate and lipid production of (0.827 d(-1), 0.688 g L-1), (0.762 d(-1), 0.961 g L-1), and (0.728 d(-1), 0.792 g L-1), respectively. This study demonstrated that Chlorella sp. MTF-15 could efficiently utilize the CO2, NOX and SO2 present in the different flue gases. The results also showed that the growth potential, lipid production and fatty acid composition of the microalgal strain were dependent on the composition of the flue gas and on the operating strategy deployed. (C) 2014 Elsevier Ltd. All rights reserved.