Transcript Consequences in the use of Genetically Modified Organisms

Genetically Modified Organisms
for Bulk Chemical Production
Leo van Overbeek
Outline presentation





Introduction
Risk evaluations
‘White’ and ‘Green’ biotechnology for bulk
chemical production
Bulk chemical production in the future
Conclusions
Background

Research at Plant
Research International,
Wageningen



Construction of genetically
modified plants: disease
suppression, qualitative
aspects, optimization
(marker-free GM plants)
GMO acceptance (reports,
discussions)
Soil biology (GMO impact
analysis)
Introduction

Bulk chemical production


Production by making use of Genetically Modified
Organisms (GMOs)



E.g. Polyhydroxyalkanoate (PHA)
Optimal yield
Chemical modification
‘White’ Biotechnology (contained use) and ‘Green’
Biotechnology (GM plants in open fields)
Goal
Overview of prospects and limitations in the
application of GMOs for bulk chemical production

Emphasis on



‘White’ Biotechnology
Effects on nature and food chains
Knowledge gaps for future (large quantity) production
Risk evaluation and public perception


Release of GMO will always occur
What are the events after GMO release
In order of severity:
1.
Effect (neutral)
2.
Hazard (negative consequence)
3.
Risk (impact)

Risk assessment:


Risk = chance of hazard x exposure (volume/ time)
Public perception on modern biotechnology
(occasionally no rational arguments used in discussions)
Non-rational arguments



Field experiment with a
GM potato line
Aimed to establish
possible effects on the
indigenous soil and plantassociated microflora
Field destroyed by activists
From literature


Field release studies with GM bacteria and plants
GM plants and micro-organisms are constructed
to demonstrate an effect (worst case)


No effects observed
Or only transient effects observed
No obvious hazards could be find in literature!
Use of GMOs for bulk chemical production

Effect on food chains


PHA is non-toxic and non-allergenic
Effects on natural environments

PHA is biodegradable
No impact on consumption goods and natural
environments expected!
GMO effect after release
Effect
Measure
Recombinant gene expression
Controlled regulation of recombinant gene
construct
GMO survival and spread
Physiologically impaired host (e.g.
auxotrophic strains)
Containment genes
Gene transfer
Recombinant DNA insertion in non-mobile
constructs
Gene type
1)
2)
Genes whose products do not have
obvious effects on other organisms
Assessment for genes whose
products have an effect
Limitations to evaluate consequences of GMO
releases
0.8

Analytical tools
FW

Universal DGGE
flowering
FD

FW FD
FD
Technical limitations for
detection
Environmental impact
FW

transgenic
wildtype
YW
YW
SW
-0.6
YD
YD
SD
SW
senescent

YD
SD
young

YW
SD
-0.8
Ecology

SW
Where to compare with?
Natural fluctuations are large
and not always understood
0.8

Not all organisms are
described (soil)
Not all interactions are clear
‘White’ Biotechnology


Contained use of micro-organisms (or biotechnological
derivatives) for production of e.g. enzymes and bulk
chemicals
Use of renewable raw materials and advanced enzyme
systems, replacing fossil raw materials






bio-energy
biomaterials
bulk chemicals
Direct: e.g. bulk chemicals like PHA
Indirect: production of enzymes required for bulk chemical
production
Realistic for industry
PHA production in closed systems
Construct
Reference
Ralstonia eutropha with phaC from Fukui and Doi 1997 and 1998.
Aeromonas punctata
Aeromonas hydrophila with yafH
from E. coli
Lu et al., 2004
A. Hydrophila with phaPCJ genes
from A. punctata
Han et al., 2004
Arxula adeninivorans with phbABC Terentiev et al., 2004
genes from R. eutropha
Recommendations for ‘white’ biotechnology

Microbial host



Recombinant gene




Suitable for optimization (growth properties, nutrient requirements)
Containment (loss of viability after release)
Possibilities for modification of the product
Control on gene regulation
Containment genes (killing of host after accidental release)
Waste


Other applications
Eradication of living GMOs in waste products
‘Green’ Biotechnology


Genetically modified plants in fields
Open production facilities



Possibility of free exchange of GM materials with the
environment and food chains
Coexistence between agricultural systems
(controversy organic – conventional farming)
Lower emphasis for industry
PHA production by plants
Construct
Reference
Flax (Linum usitatissimum)
with phbABC genes from R.
eutropha
Wróbel et al., 2004
Tobacco (Nicotiana
tabacum) with phbABC
genes from R. eutropha
Arai et al., 2004
Requirements for ‘Green’ biotechnology

Plant host



Recombinant gene



Choice of best performing crops for bulk chemical
production
Preference for non-food crops
Marker-free constructs
Restrictions on sexual exchange of rec DNA (e.g.
plastid transformation)
Logistics to keep GMO seeds separated from
non-GMO seeds
Seed logistics
White Biotechnology
Green Biotechnology
(contained use of GM micro-
(Growth of GM plants
Organisms)
in open fields)
waste
Crop wastes
(GMO still viable)
Other applications
(viability of GMO)
Waste after processing
(nonviable GMO material)
Bulk chemical production

Application of GM microbes for bulk chemical
production under contained conditions is realistic



Safe production
Containment guaranteed
Applications of GM plants in open fields is
uncertain and thus less realistic


Containment in open fields is difficult to maintain
Post harvest measures are required (transport,
storage, raw material treatments)
Prospects




‘White’ biotechnology will become important for
bulk chemical production
Production with GM micro-organisms in closed
reactors will largely increase
Risk assessment must be adapted for largerscale production facilities
Processing of fermentation waste products will
become important
Expected scale enlargement
White Biotechnology
Environmental-friendly production
Adaptations:
Production facilities
Biological containment
Wastes
Consequences
Increased biotechnological production means:
 Less chemicals and energy required
 Less toxic wastes produced
 More emphasis on containment



Infrastructure (input raw materials, processing)
Biological containment (facilities and constructs)
Increased organic waste from reactors

Concern for living GMOs in products made out of
waste
Solutions


Technical improvement of production facilities,
circumstances and GMO constructs
Alternative use of waste from fermentation
reactors

Agricultural use; e.g. by composting and heat
inactivation or recycling of waste compounds
Conclusions





Only temporal effects have been observed in small-scale
GMO release studies
GM constructs for bulk chemical production must be
qualified as ‘low in risk’
No effect can be expected with the application of GM
microbes for bulk chemical production in ‘white’
biotechnology
Uncertainties exist with increased scale and long-term
production with GM plants
Waste products from fermentation reactors must be
processed and free of living GMOs
Knowledge gaps



Present analytical tools may be too limited to
detect effects by increased-scale and long-term
production; special emphasis on GM plant
production
Ecological baseline knowledge to discriminate
GMO from non-GMO effects
Relevant information on ecological interactions
between species (e.g. what can be the effect of
elevated levels of PHA on different populations)