Abstract

Escalating concerns about CO2 emission from fossil fuel utilization and environmental pollution from fossil-derived plastic waste call for the sustainable production and utilization of renewable biodegradable plastic materials. Polyhydroxyalkanoates (PHAs) are biodegradable and biocompatible thermoplastics with thermal and mechanical properties comparable to conventional plastics; thus, they are promising materials to mitigate environmental pollution. (R)-3-Hydroxybutyrate (3HB), which is the most common building-block for PHAs, has the potential to be utilized in various medical applications and can also serve as a precursor to a variety of value-added stereospecific chemicals. In addition, it can be produced by microorganisms, such as engineered cyanobacteria, from inexpensive renewable resources such as waste CO2. However, higher titer and rate of (R)-3HB production by cyanobacteria beyond that found in the current literature are critical for commercial applications. Herein, we employed a facile strategy to identify the rate-limiting step in the photoautotrophic production of (R)-3HB by the cyanobacterium Synechocystis and found that acetoacetyl-CoA reductase activity is the bottleneck in the process. Optimization of the gene's ribosome binding site led to a 2.2-fold increase in enzyme activity. In the culture medium of the engineered organism, the (R)-3HB titer reached 1.84 g L-1 within 10 days, with a peak productivity of 263 mg L-1 day-1, using CO2 and light as the sole carbon and energy sources. Moreover, dramatic changes in carbon partition were discovered in the (R)-3HB-producing cells along the course of cultivation using 13C-metabolic flux analysis; after the rapid growth phase, a majority of carbon flux was redirected from the cell mass formation to the production of (R)-3HB in the engineered Synechocystis under the examined experimental conditions.

Original languageEnglish (US)
Pages (from-to)3772-3782
Number of pages11
JournalGreen Chemistry
Volume20
Issue number16
DOIs
StatePublished - Jan 1 2018

Fingerprint

3-Hydroxybutyric Acid
cyanobacterium
Plastics
plastic
Polyhydroxyalkanoates
Carbon
plastic waste
Pollution
carbon
renewable resource
carbon flux
Fluxes
fossil fuel
enzyme activity
mechanical property
Enzyme activity
Medical applications
Binding sites
microorganism
Fossil fuels

ASJC Scopus subject areas

  • Environmental Chemistry
  • Pollution

Cite this

Unlocking the photobiological conversion of CO2 to ( : R)-3-hydroxybutyrate in cyanobacteria. / Wang, Bo; Xiong, Wei; Yu, Jianping; Maness, Pin Ching; Meldrum, Deirdre.

In: Green Chemistry, Vol. 20, No. 16, 01.01.2018, p. 3772-3782.

Research output: Contribution to journalArticle

Wang, Bo ; Xiong, Wei ; Yu, Jianping ; Maness, Pin Ching ; Meldrum, Deirdre. / Unlocking the photobiological conversion of CO2 to ( : R)-3-hydroxybutyrate in cyanobacteria. In: Green Chemistry. 2018 ; Vol. 20, No. 16. pp. 3772-3782.
@article{f441d3bb16204d8dad8546956c013bbb,
title = "Unlocking the photobiological conversion of CO2 to (: R)-3-hydroxybutyrate in cyanobacteria",
abstract = "Escalating concerns about CO2 emission from fossil fuel utilization and environmental pollution from fossil-derived plastic waste call for the sustainable production and utilization of renewable biodegradable plastic materials. Polyhydroxyalkanoates (PHAs) are biodegradable and biocompatible thermoplastics with thermal and mechanical properties comparable to conventional plastics; thus, they are promising materials to mitigate environmental pollution. (R)-3-Hydroxybutyrate (3HB), which is the most common building-block for PHAs, has the potential to be utilized in various medical applications and can also serve as a precursor to a variety of value-added stereospecific chemicals. In addition, it can be produced by microorganisms, such as engineered cyanobacteria, from inexpensive renewable resources such as waste CO2. However, higher titer and rate of (R)-3HB production by cyanobacteria beyond that found in the current literature are critical for commercial applications. Herein, we employed a facile strategy to identify the rate-limiting step in the photoautotrophic production of (R)-3HB by the cyanobacterium Synechocystis and found that acetoacetyl-CoA reductase activity is the bottleneck in the process. Optimization of the gene's ribosome binding site led to a 2.2-fold increase in enzyme activity. In the culture medium of the engineered organism, the (R)-3HB titer reached 1.84 g L-1 within 10 days, with a peak productivity of 263 mg L-1 day-1, using CO2 and light as the sole carbon and energy sources. Moreover, dramatic changes in carbon partition were discovered in the (R)-3HB-producing cells along the course of cultivation using 13C-metabolic flux analysis; after the rapid growth phase, a majority of carbon flux was redirected from the cell mass formation to the production of (R)-3HB in the engineered Synechocystis under the examined experimental conditions.",
author = "Bo Wang and Wei Xiong and Jianping Yu and Maness, {Pin Ching} and Deirdre Meldrum",
year = "2018",
month = "1",
day = "1",
doi = "10.1039/c8gc01208c",
language = "English (US)",
volume = "20",
pages = "3772--3782",
journal = "Green Chemistry",
issn = "1463-9262",
publisher = "Royal Society of Chemistry",
number = "16",

}

TY - JOUR

T1 - Unlocking the photobiological conversion of CO2 to (

T2 - R)-3-hydroxybutyrate in cyanobacteria

AU - Wang, Bo

AU - Xiong, Wei

AU - Yu, Jianping

AU - Maness, Pin Ching

AU - Meldrum, Deirdre

PY - 2018/1/1

Y1 - 2018/1/1

N2 - Escalating concerns about CO2 emission from fossil fuel utilization and environmental pollution from fossil-derived plastic waste call for the sustainable production and utilization of renewable biodegradable plastic materials. Polyhydroxyalkanoates (PHAs) are biodegradable and biocompatible thermoplastics with thermal and mechanical properties comparable to conventional plastics; thus, they are promising materials to mitigate environmental pollution. (R)-3-Hydroxybutyrate (3HB), which is the most common building-block for PHAs, has the potential to be utilized in various medical applications and can also serve as a precursor to a variety of value-added stereospecific chemicals. In addition, it can be produced by microorganisms, such as engineered cyanobacteria, from inexpensive renewable resources such as waste CO2. However, higher titer and rate of (R)-3HB production by cyanobacteria beyond that found in the current literature are critical for commercial applications. Herein, we employed a facile strategy to identify the rate-limiting step in the photoautotrophic production of (R)-3HB by the cyanobacterium Synechocystis and found that acetoacetyl-CoA reductase activity is the bottleneck in the process. Optimization of the gene's ribosome binding site led to a 2.2-fold increase in enzyme activity. In the culture medium of the engineered organism, the (R)-3HB titer reached 1.84 g L-1 within 10 days, with a peak productivity of 263 mg L-1 day-1, using CO2 and light as the sole carbon and energy sources. Moreover, dramatic changes in carbon partition were discovered in the (R)-3HB-producing cells along the course of cultivation using 13C-metabolic flux analysis; after the rapid growth phase, a majority of carbon flux was redirected from the cell mass formation to the production of (R)-3HB in the engineered Synechocystis under the examined experimental conditions.

AB - Escalating concerns about CO2 emission from fossil fuel utilization and environmental pollution from fossil-derived plastic waste call for the sustainable production and utilization of renewable biodegradable plastic materials. Polyhydroxyalkanoates (PHAs) are biodegradable and biocompatible thermoplastics with thermal and mechanical properties comparable to conventional plastics; thus, they are promising materials to mitigate environmental pollution. (R)-3-Hydroxybutyrate (3HB), which is the most common building-block for PHAs, has the potential to be utilized in various medical applications and can also serve as a precursor to a variety of value-added stereospecific chemicals. In addition, it can be produced by microorganisms, such as engineered cyanobacteria, from inexpensive renewable resources such as waste CO2. However, higher titer and rate of (R)-3HB production by cyanobacteria beyond that found in the current literature are critical for commercial applications. Herein, we employed a facile strategy to identify the rate-limiting step in the photoautotrophic production of (R)-3HB by the cyanobacterium Synechocystis and found that acetoacetyl-CoA reductase activity is the bottleneck in the process. Optimization of the gene's ribosome binding site led to a 2.2-fold increase in enzyme activity. In the culture medium of the engineered organism, the (R)-3HB titer reached 1.84 g L-1 within 10 days, with a peak productivity of 263 mg L-1 day-1, using CO2 and light as the sole carbon and energy sources. Moreover, dramatic changes in carbon partition were discovered in the (R)-3HB-producing cells along the course of cultivation using 13C-metabolic flux analysis; after the rapid growth phase, a majority of carbon flux was redirected from the cell mass formation to the production of (R)-3HB in the engineered Synechocystis under the examined experimental conditions.

UR - http://www.scopus.com/inward/record.url?scp=85051547669&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85051547669&partnerID=8YFLogxK

U2 - 10.1039/c8gc01208c

DO - 10.1039/c8gc01208c

M3 - Article

VL - 20

SP - 3772

EP - 3782

JO - Green Chemistry

JF - Green Chemistry

SN - 1463-9262

IS - 16

ER -