title: Identification of carbohydrates as the major carbon sink of the marine microalga Isochrysis zhangjiangensis (Haptophyta) and optimization of its productivity by nitrogen manipulation.
abstract: Microalgae represent a potential feedstock for biofuel production. During cultivation under nitrogen-depleted conditions, carbohydrates, rather than neutral lipids, were the major carbon sink of the marine microalga Isochrysis zhangjiangensis (Haptophyta). Carbohydrates reached maximum levels of 21.2 pg cell(-1) on day 5, which was an increase of more than 7-fold from day 1, while neutral lipids simultaneously increased 1.9-fold from 4.0 to 7.6 pg cell(-1) during the ten-day nitrogen-depleted cultivation. The carbohydrate productivity of I. zhangjiangensis was improved by optimization of the nitrate supply mode. The maximum carbohydrate concentration was 0.95 g L(-1) under batch cultivation, with an initial nitrogen concentration of 31.0 mg L(-1), which was 2.4-fold greater than that achieved under nitrogen-depleted conditions. High performance liquid chromatography (HPLC) analysis showed that the accumulated carbohydrate in I. zhangjiangensis was composed of glucose. These results show that I. zhangjiangensis represents an ideal carbohydrate-enriched bioresource for biofuel production.
authors.affiliation: Marine Bioproducts Engineering Group, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Hai-Tao
authors.initials: HT
authors.lastname: Wang
authors.affiliation: Marine Bioproducts Engineering Group, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
authors.forename: Chang-Hong
authors.initials: CH
authors.lastname: Yao
authors.affiliation: Marine Bioproducts Engineering Group, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
authors.forename: Jiang-Ning
authors.initials: JN
authors.lastname: Ai
authors.affiliation: Marine Bioproducts Engineering Group, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
authors.forename: Xu-Peng
authors.initials: XP
authors.lastname: Cao
authors.affiliation: Marine Bioproducts Engineering Group, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China. Electronic address: xuesong@dicp.ac.cn.
authors.forename: Song
authors.initials: S
authors.lastname: Xue
authors.affiliation: State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China.
authors.forename: Wei-liang
authors.initials: WL
authors.lastname: Wang
mesh_terms: D056804:Biofuels; D019149:Bioreactors; D057965:Carbon Sequestration / Q000502:physiology*; D002851:Chromatography, High Pressure Liquid; D005947:Glucose / Q000502:physiology*; D058087:Haptophyta / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D058086:Microalgae / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D009566:Nitrates / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism*; D045332:Photosystem II Protein Complex / Q000378:metabolism
chemical_list: D056804:Biofuels; D009566:Nitrates; D045332:Photosystem II Protein Complex; D005947:Glucose; D009584:Nitrogen
keywords: Carbohydrate production; Isochrysis zhangjiangensis; Microalga carbohydrate; Nitrogen limitation