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Title: Engineering Cyanobacterial Cell Morphology for Enhanced Recovery and Processing of Biomass

Abstract

ABSTRACT Cyanobacteria are emerging as alternative crop species for the production of fuels, chemicals, and biomass. Yet, the success of these microbes depends on the development of cost-effective technologies that permit scaled cultivation and cell harvesting. Here, we investigate the feasibility of engineering cell morphology to improve biomass recovery and decrease energetic costs associated with lysing cyanobacterial cells. Specifically, we modify the levels of Min system proteins inSynechococcus elongatusPCC 7942. The Min system has established functions in controlling cell division by regulating the assembly of FtsZ, a tubulin-like protein required for defining the bacterial division plane. We show that altering the expression of two FtsZ-regulatory proteins, MinC and Cdv3, enables control over cell morphology by disrupting FtsZ localization and cell division without preventing continued cell growth. By varying the expression of these proteins, we can tune the lengths of cyanobacterial cells across a broad dynamic range, anywhere from an ∼20% increased length (relative to the wild type) to near-millimeter lengths. Highly elongated cells exhibit increased rates of sedimentation under low centrifugal forces or by gravity-assisted settling. Furthermore, hyperelongated cells are also more susceptible to lysis through the application of mild physical stress. Collectively, these results demonstrate a novel approach towardmore » decreasing harvesting and processing costs associated with mass cyanobacterial cultivation by altering morphology at the cellular level. IMPORTANCEWe show that the cell length of a model cyanobacterial species can be programmed by rationally manipulating the expression of protein factors that suppress cell division. In some instances, we can increase the size of these cells to near-millimeter lengths with this approach. The resulting elongated cells have favorable properties with regard to cell harvesting and lysis. Furthermore, cells treated in this manner continue to grow rapidly at time scales similar to those of uninduced controls. To our knowledge, this is the first reported example of engineering the cell morphology of cyanobacteria or algae to make them more compatible with downstream processing steps that present economic barriers to their use as alternative crop species. Therefore, our results are a promising proof-of-principle for the use of morphology engineering to increase the cost-effectiveness of the mass cultivation of cyanobacteria for various sustainability initiatives.« less

Authors:
; ; ; ; ; ;
Publication Date:
Research Org.:
Michigan State Univ., East Lansing, MI (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1536856
DOE Contract Number:  
FG02-91ER20021
Resource Type:
Journal Article
Journal Name:
Applied and Environmental Microbiology
Additional Journal Information:
Journal Volume: 83; Journal Issue: 9; Journal ID: ISSN 0099-2240
Publisher:
American Society for Microbiology
Country of Publication:
United States
Language:
English
Subject:
Biotechnology & Applied Microbiology; Microbiology

Citation Formats

Jordan, Adam, Chandler, Jenna, MacCready, Joshua S., Huang, Jingcheng, Osteryoung, Katherine W., Ducat, Daniel C., and Pettinari, M. Julia. Engineering Cyanobacterial Cell Morphology for Enhanced Recovery and Processing of Biomass. United States: N. p., 2017. Web. doi:10.1128/aem.00053-17.
Jordan, Adam, Chandler, Jenna, MacCready, Joshua S., Huang, Jingcheng, Osteryoung, Katherine W., Ducat, Daniel C., & Pettinari, M. Julia. Engineering Cyanobacterial Cell Morphology for Enhanced Recovery and Processing of Biomass. United States. doi:10.1128/aem.00053-17.
Jordan, Adam, Chandler, Jenna, MacCready, Joshua S., Huang, Jingcheng, Osteryoung, Katherine W., Ducat, Daniel C., and Pettinari, M. Julia. Fri . "Engineering Cyanobacterial Cell Morphology for Enhanced Recovery and Processing of Biomass". United States. doi:10.1128/aem.00053-17.
@article{osti_1536856,
title = {Engineering Cyanobacterial Cell Morphology for Enhanced Recovery and Processing of Biomass},
author = {Jordan, Adam and Chandler, Jenna and MacCready, Joshua S. and Huang, Jingcheng and Osteryoung, Katherine W. and Ducat, Daniel C. and Pettinari, M. Julia},
abstractNote = {ABSTRACT Cyanobacteria are emerging as alternative crop species for the production of fuels, chemicals, and biomass. Yet, the success of these microbes depends on the development of cost-effective technologies that permit scaled cultivation and cell harvesting. Here, we investigate the feasibility of engineering cell morphology to improve biomass recovery and decrease energetic costs associated with lysing cyanobacterial cells. Specifically, we modify the levels of Min system proteins inSynechococcus elongatusPCC 7942. The Min system has established functions in controlling cell division by regulating the assembly of FtsZ, a tubulin-like protein required for defining the bacterial division plane. We show that altering the expression of two FtsZ-regulatory proteins, MinC and Cdv3, enables control over cell morphology by disrupting FtsZ localization and cell division without preventing continued cell growth. By varying the expression of these proteins, we can tune the lengths of cyanobacterial cells across a broad dynamic range, anywhere from an ∼20% increased length (relative to the wild type) to near-millimeter lengths. Highly elongated cells exhibit increased rates of sedimentation under low centrifugal forces or by gravity-assisted settling. Furthermore, hyperelongated cells are also more susceptible to lysis through the application of mild physical stress. Collectively, these results demonstrate a novel approach toward decreasing harvesting and processing costs associated with mass cyanobacterial cultivation by altering morphology at the cellular level. IMPORTANCEWe show that the cell length of a model cyanobacterial species can be programmed by rationally manipulating the expression of protein factors that suppress cell division. In some instances, we can increase the size of these cells to near-millimeter lengths with this approach. The resulting elongated cells have favorable properties with regard to cell harvesting and lysis. Furthermore, cells treated in this manner continue to grow rapidly at time scales similar to those of uninduced controls. To our knowledge, this is the first reported example of engineering the cell morphology of cyanobacteria or algae to make them more compatible with downstream processing steps that present economic barriers to their use as alternative crop species. Therefore, our results are a promising proof-of-principle for the use of morphology engineering to increase the cost-effectiveness of the mass cultivation of cyanobacteria for various sustainability initiatives.},
doi = {10.1128/aem.00053-17},
journal = {Applied and Environmental Microbiology},
issn = {0099-2240},
number = 9,
volume = 83,
place = {United States},
year = {2017},
month = {2}
}