Database Product Description
- Host Organism
- Zea mays (Maize)
- Modified amylase for ethanol production
- Trait Introduction
- Agrobacterium tumefaciens-mediated plant transformation.
- Proposed Use
Production of maize grain primarily for industrial ethanol.
- Product Developer
- Syngenta Seeds, Inc.
Summary of Regulatory Approvals
Summary of Introduced Genetic Elements Expand
Characteristics of Zea mays (Maize) Expand
Modification Method Expand
Characteristics of the Modification Expand
Environmental Safety Considerations Expand
Food and/or Feed Safety Considerations Expand
Maize line 3272 (OECD identifier SYN-E3272-5) contains two novel genes. The first, the amy797E gene, encodes the thermostable AMY797E alpha-amylase enzyme. alpha-Amylase catalyses the hydrolysis of starch by cleaving the internal alpha-1,4-glucosidic bonds into dextrins, maltose and glucose. The chimeric amy797E gene is derived from three wild-type alpha-amylase genes from the archael order Thermococcales. The amy797E gene encoded protein was selected for further development due to its thermostability, catalytic activity and reduced dependency on calcium under acidic conditions. These properties are important for the commercial application of alpha-amylase in the enzymatic hydrolysis of starch in dry-grind ethanol production from maize. The second gene, pmi (manA), derived from Escherichia coli, encodes the enzyme phosphomannose isomerase (PMI). The pmi gene is used as a selectable marker gene in the corn transformation process. Molecular and genetic analyses indicate that the transferred genes are stably integrated into the plant genome at one insertion site and are stably inherited from one generation to the next.
The majority of maize is grown for animal feed production and human food, however an increasing percentage is being used for the production of ethanol as a biofuel alternative to petroleum products from fossil sources. The hydrolysis of the large starch molecules in maize kernels is the first step in ehtanol production from maize and the themostable alpha-amylase in Event 3272 is intended to increase the efficiency of this process by operating at high temperatures. Although Event 3272 is not intended to be used directly for animal feed or human consumption, the residue remaining after starch hydrolysis and ethanol fermentation is used for animal feed, referred to as distillers dried grains with solubles (DDGS). There is also a possibility that grains of Event 3272 will enter the human food and animal feed chain through adventitious presence in other lots of maize grown for these purposes. As such, the event has been reviewed for both human food and animal feed safety, with no indications that there is any increased risk form inclusion of this event in the food and feed chains. One possible outcome, that the thermostable alpha-amylase may remain active during processing and hydrolyse starch thereby increasing the glycemic index of the final food product. However, even if the final food’s glycemic index was increased, the overall effect on the diet would be minimal given that glycemic index is heavily influenced by other dietary factors.
Event 3272 has been assessed for environmental impact and it was determined that there are no biologically meaningful differences between the event and isogenic non-transgenic counterparts with regards to plant pest potential, weediness or invasive potential. The novel proteins expressed in Event 3272 are not toxic in acute oral toxicity tests and show no homology to known toxins, indicating a minimal risk to non-target organisms in the environment exposed to the proteins in Event 3272. There are no phenotypic chracteristics in Event 3272 that would extend its range beyond that of conventional corn production and, together with the lack of any impact on non-target organisms, provides evidence to conclude that the potential impact of Event 3272 on the environment and biodiversity is equivalent to that of conventional maize varieties.
Links to Further Information Expand
This record was last modified on Wednesday, November 9, 2016