Genetically Modified Organisms for Bulk Chemical ProductionLeo 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 E.g. Polyhydroxyalkanoate (PHA)

Production by making use of Genetically Modified Organisms (GMOs) 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 plant-associated 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) Genes whose products do not have obvious effects on other organisms

2) Assessment for genes whose products have an effect

Limitations to evaluate consequences of GMO releases

Analytical tools Technical limitations for

detection Environmental impact

Where to compare with? Natural fluctuations are

large and not always understood

Ecology Not all organisms are

described (soil) Not all interactions are

clear

-0.8 0.8

-0.6

0.8

YWYW

YW

YDYD

YD

FW

FW

FW

FD

FD

FD

SW

SW

SW

SD

SD

SD

wildtype

transgenic

young

flowering

senescent

Universal DGGE

‘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 Aeromonas punctata

Fukui and Doi 1997 and 1998.

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 genes from R. eutropha

Terentiev et al., 2004

Recommendations for ‘white’ biotechnology Microbial host

Suitable for optimization (growth properties, nutrient requirements)

Containment (loss of viability after release) Recombinant gene

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 Choice of best performing crops for bulk

chemical production Preference for non-food crops

Recombinant gene 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

(contained use of GM micro-

Organisms)

Green Biotechnology

(Growth of GM plants

in open fields)

Other applications

(viability of GMO)

wasteCrop wastes

(GMO still viable)

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 larger-scale production facilities

Processing of fermentation waste products will become important

time

White BiotechnologyExpected scale enlargement

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)