Science - December 1, 2011

Useful chemical from organic waste

Chemicals can be manufactured from certain amino acids in organic waste. And it is both technically and economically viable, concludes Tijs Lammens.

Glutamic acid
Lammens researched the applications of glutamic acid, which is present in numerous proteins in organic waste flows.
Glutamic acid is what is called a non-essential amino acid: it has little nutritional value. But in its pure form it is a neurotransmitter, regulating our mood for example. Lammens had a very different application in mind though, namely as a building block for nitrogen-fixing chemicals. These substances are currently extracted from crude oil or natural gas, which takes a lot of energy. Lammens researched a production method with glutamic acid as raw material.

In several stages of a chemical process, he converted the glutamic acid into N-methylpyrrolidon (NMP), a much-used solvent and into N-vinylpurrolidon (NVP), a constituent of glue. He concluded that producing these two substances from glutamic acid is technically feasible and that the production costs are probably no higher than those of making it from fossil fuels.
 Lammens works on a lab scale and has not yet made a kilo of NMP and NVP. But he has designed a model production facility, enabling him to make a rough estimate of the costs of resources, energy consumption and process technology. 'Then production seems possible', says the PhD researcher.
 Chemical producers DSM and BASF were involved in Lammens' research. So are they going to apply it?  'BASF, which now makes these substances from crude oil was pretty critical. The production of NMP and NVP from crude oil is part of a larger process that cannot be converted just like that. I think it's more likely that another company will invest in this biobased production method. For example, in Rotterdam there is a bioethanol factory that produces 500 million litres of alcohol per year. That leads to 360 million kilos of a by-product containing 36 million kilos of glutamic acid, which could be turned into 23 million kilos of NMP. The turnover on the world market is 150 million kilos. So you can see that it has quite some potential.
 But a cost-effective method of extracting glutamic acid from organic waste flows will need to be found, says Lammens. One of those working on this is his colleague in the chair group, Yinglai Teng.
 Tijs Lammens will receive his PhD on 2 December from Johan Sanders, professor of Valorisation of Plant Production Chains.

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