Browsing by Author "Lai, Jinn-Tsyy"

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Ability of an alkali-tolerant mutant strain of the microalga Chlorella sp AT1 to capture carbon dioxide for increasing carbon dioxide utilization efficiency
(2017-11-01)
Kuo, Chiu-Mei
;
Lin, Tsung-Hsien
;
Yang, Yi-Chun
;
Zhang, Wen-Xin
;
Lai, Jinn-Tsyy
An alkali-tolerant Chlorella sp. AT1 mutant strain was screened by NTG mutagenesis. The strain grew well in pH 6-11 media, and the optimal pH for growth was 10. The CO2 utilization efficiencies of Chlorella sp. AT1 cultured with intermittent 10% CO2 aeration for 10, 20 and 30 min at 3-h intervals were approximately 80, 42 and 30%, respectively. In alkaline medium (pH = 11) with intermittent 10% CO2 aeration for 30 min at 3-, 6- and 12-h intervals, the medium pH gradually changed to 10, and the biomass productivities of Chlorella sp. AT1 were 0.987, 0.848 and 0.710 g L-1 d(-1), respectively. When Chlorella sp. AT1 was aerated with 10% CO2 intermittently for 30 min at 3-h intervals in semi-continuous cultivation for 21 days, the biomass concentration and biomass productivity were 4.35 g L-1 and 0.726 g L-1 d(-1), respectively. Our results show that CO2 utilization efficiency can be markedly increased by intermittent CO2 aeration and alkaline media as a CO2-capturing strategy for alkali-tolerant microalga cultivation.
An efficient Photobioreactors/Raceway circulating system combined with alkaline-CO2 capturing medium for microalgal cultivation
(2018-10-01)
Kuo, Chiu-Mei
;
Jian, Jhong-Fu
;
Sun, Yu-Ling
;
Lin, Tsung-Hsien
;
Yang, Yi-Chun
High efficiency of microalgal growth and CO2 fixation in a Photobioreactors (PBRs)/Raceway circulating (PsRC) system combined with alkaline-CO2 capturing medium and operation was established and investigated. Compared with a pH 6 medium, the average biomass productivity of Chlorella sp. AT1 cultured in a pH 11 medium at 2L min(-1) circulation rate for 7 days increased by about 2-fold to 0.346g L-1 d(-1). The maximum amount of CO2 fixation and CO2 utilization efficiency of Chlorella sp. AT1 could be obtained at a PBRs to Raceway ratio of 1:10 in an indoor-simulated PsRC system. A similar result was also shown in an outdoor PsRC system with a 10-ton scale for microalgal cultivation. Under the appropriate circulation rate, the stable growth performance of Chlorella sp. AT1 cultured by long-term semi-continuous operation in the 10-ton outdoor PsRC system was observed, and the total amount of CO2 fixation was approximately 1.2kg d(-1) with 50% CO2 utilization efficiency.
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.
Simultaneous microalgal biomass production and CO2 fixation by cultivating Chlorella sp GD with aquaculture wastewater and boiler flue gas
(2016-12)
Kuo, Chiu-Mei
;
Jian, Jhong-Fu
;
Lin, Tsung-Hsien
;
Chang, Yu-Bin
;
Wan, Xin-Hua
A microalgal strain, Chlorella sp. GD, cultivated in aquaculture wastewater (AW) aerated with boiler flue gas, was investigated. When AW from a grouper fish farm was supplemented with additional nutrients, the microalgal biomass productivity after 7 days of culture was 0.794 g L-1 d(-1). CO2 fixation efficiencies of the microalgal strains aerated with 0.05, 0.1, 0.2, and 0.3 vvm of boiler flue gas (containing approximately 8% CO2) were 53, 51, 38, and 30%, respectively. When the microalgal strain was cultured with boiler flue gas in nutrient-added AW, biomass productivity increased to 0.892 g L-1 d(-1). In semi-continuous cultures, average biomass productivities of the microalgal strain in 2-day, 3-day, and 4-day replacement cultures were 1.296, 0.985, and 0.944 g L-1 d(-1), respectively. These results demonstrate the potential of using Chlorella sp. GD cultivations in AW aerated with boiler flue gas for reusing water resources, reducing CO2 emission, and producing microalgal biomass. (C) 2016 Elsevier Ltd. All rights reserved.