Huge potential for bioplastics

Jul 17, 2006
Huge potential for bioplastics

It almost sounds too good to be true - turning cow pats into plastic. But the unlikely-looking liquid in the flask Dr Steven Pratt holds is the key ingredient to an environmentally friendlier drink bottle.

The murky mix of acids is produced by fermenting bacteria taken from wastewater ponds and fed with a glucose solution. A glucose solution is used in this laboratory situation, but the bacteria will feed with equal efficiency on dairy-farm effluent or other carbon-based wastewater.

It is the renewable and biodegradable nature of such ingredients that give the types of plastic produced from the acids the classification of ‘bio-plastics’.

A researcher in the Centre for Environmental Technology and Engineering, Dr Pratt says the potential for bioplastic production in New Zealand is huge.

“The waste produced by our agricultural and pulp and paper industries is ideal, and there is so much of it.”

He says plastics are a major environmental problem as they are non-biodegradable and their production from synthetic polymers consumes vast quantities of non-renewable resources.

“By using cheap and renewable sources there is a tremendous opportunity for biopolymer production to be made economic. At the same time, the problems of wastewater treatment and natural resource depletion are addressed.”

He says some acids are better than others for the production of bio-plastic. For example, acetic acid-based plastic is comparatively brittle to that produced from other acids; it has been shown that the inclusion of propionic acid produces polymer chains (the building blocks of plastic) with the favourable characteristic of malleability.

The task of producing one particular acid, however, is complicated by the diversity of the constituents of raw wastewater and effluent.

Part of Dr Pratt’s project looks at controlling the fermentation procedure by adjusting factors such as pH so that only one kind of acid is produced. His team of postgraduate students are also focusing on a stage in the fermentation process that is typically ignored.

“Fermentation has been around for thousands of years, and the science of fermentation has been understood for quite some time, but no-one has really looked at what happens in transient stages.”

A transient stage occurs when bacteria are shocked by the input of food (in this case, carbon-based effluent) or when conditions such as pH are altered. The micro-organisms react to these changes in interesting ways before evening out and producing a consistent volume of mixed acids.

“In this transient stage one type of acid may be made in greater proportions, and other unknown or unexpected compounds can also be made. Sometimes the most interesting things are made when things go wrong.”

Source: Massey University

Explore further: New technique reveals immune cell motion through variety of tissues

add to favorites email to friend print save as pdf

Related Stories

Underfire Uber ramps up rider safety

6 hours ago

Uber is ramping up driver background checks and other security measures worldwide after the smartphone-focused car-sharing service was banned in New Delhi following the alleged rape of a passenger.

US probe links NKorea to Sony hacking

6 hours ago

A U.S. official says federal investigators have now connected the Sony Pictures Entertainment Inc. hacking to North Korea and are expected to make an announcement in the near future.

New York state bans fracking

6 hours ago

Governor Andrew Cuomo said Wednesday he would ban hydraulic fracking in New York State, citing health concerns about the controversial oil and gas drilling technique.

Sony cancels NKorea parody film release after threats

6 hours ago

Hollywood studio Sony Pictures on Wednesday abruptly canceled the December 25 release date of "The Interview," a parody film which has angered North Korea and triggered chilling threats from hackers.

Recommended for you

'Global positioning' for molecules

Dec 19, 2014

In everyday life, the global positioning system (GPS) can be employed to reliably determine the momentary location of one en route to the desired destination. Scientists from the Institute of Physical and ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.