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The role of microtubules in microalgae: promotion of lipid accumulation and extraction.

Published version
Peer-reviewed

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Authors

Zhang, Lijie 
Lin, Xiao 
Yang, Zhigang 
Jiang, Liqun 
Hou, Qingjie 

Abstract

BACKGROUND: Microtubules in cells are closely related to the growth and metabolism of microalgae. To date, the study of microalgal microtubules has mainly concentrated on revealing the relationship between microtubule depolymerization and synthesis of precursors for flagellar regeneration. While information on the link between microtubule depolymerization and biosynthesis of precursors for complex organic matter (such as lipid, carbohydrate and protein), is still lacking, a better understanding of this could help to achieve a breakthrough in lipid regulation. With the aim of testing the assumption that microtubule disruption could regulate carbon precursors and redirect carbon flow to promote lipid accumulation, Chlorella sorokiniana SDEC-18 was pretreated with different concentrations of oryzalin. RESULTS: Strikingly, microalgae that were pretreated with 1.5 mM oryzalin accumulated lipid contents of 41.06%, which was attributed to carbon redistribution induced by microtubule destruction. To promote the growth of microalgae, two-stage cultivation involving microtubule destruction was employed, which resulted in the lipid productivity being 1.44 times higher than that for microalgae with routine single-stage cultivation, as well as yielding a desirable biodiesel quality following from increases in monounsaturated fatty acid (MUFA) content. Furthermore, full extraction of lipid was achieved after only a single extraction step, because microtubule destruction caused removal of cellulose synthase and thereby blocked cellulose biosynthesis. CONCLUSIONS: This study provides an important advance towards observation of microtubules in microalgae through immunocolloidal gold techniques combined with TEM. Moreover, the observation of efficient lipid accumulation and increased cell fragility engendered by microtubule destruction has expanded our knowledge of metabolic regulation by microtubules. Finally, two-stage cultivation involving microtubule destruction has established ideal growth, coupling enhanced lipid accumulation and efficient oil extraction; thus gaining advances in both applied and fundamental research in algal biodiesel production.

Description

Keywords

Cell fragility, Lipid accumulation, Microalgae, Microtubule destruction, Two-stage cultivation

Journal Title

Biotechnol Biofuels Bioprod

Conference Name

Journal ISSN

2731-3654
2731-3654

Volume Title

Publisher

Springer Science and Business Media LLC
Sponsorship
the National Science Fund for Excellent Young Scholars (51322811)
the Department of Science and Technology of Shandong Province (Key R&D Program (International Cooperation)) (2019GHZ030)