TAGS: Biobased Solutions
Researchers at TU Berlin are researching to replace plastics from petroleum - with the help of bacteria.
Waste Fats: Raw Material for Alternative PHA
A timid approach to dealing with plastic plague is PHA (polyhydroxyalkanoates). They are biopolymers and are used widely as they are like plastic from fossil fuels.
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Half of the two million tons of bioplastics that are currently produced worldwide per year are not biodegradable and the other half are sometimes difficult to," says Riedel. Therefore, a need arises for alternative PHA based on other raw materials.
The raw material can be obtained from many substances like corn, sugar, glycerine or palm oil. Sebastian L. Riedel and Stefan Junne, however, had a basic product that does not pollute the climate and is not food or feed such as corn as such a source material is considered problematic.
In the search for an alternative,
they decided waste fats among other things, which are incurred, inter alia, in agriculture (animal carcasses), in catering or in the processing of food waste. Trash and leftovers for others but
valuable raw materials for the scientists.
Oxy-gas Bacteria for Converting Waste into PHA
The accomplishable bacteria called Ralstonia eutropha or Cupriavidus necator, also known as oxyhydrogen bacteria. We let them 'piss us off' for us, " laughs Riedel.
The Process:
- The bacteria are kept in a mineral salt solution, fed with nitrogen, phosphorus, oxygen and carbon
- The carbon is added in the form of waste fats
- Then the bacteria are left to grow
- After a certain time, the nitrogen is removed from the bacterial culture
- They respond to this deficiency by investing the excess carbon in the waste fat as an energy reserve in their cells and converting it into PHA
- Then the PHA produced in the cells is extracted with the help of solvents, some of which can be recovered after the process
- If nitrogen is given back after a certain period, the bacteria would first use the intracellularly stored PHA as an energy source, hence it should not be done
The researchers are working on alternative refurbishment methods that will make the process more cost-effective and sustainable in the long term.
Renouncement of Research With Palm Oil
Dr.-Ing. Incidentally, Sebastian L. Riedel began his research on palm oil with PHA ten years ago in the United States at the Massachusetts Institute of Technology (MIT). "
This is a super uncomplicated starting material for the production of the substance," says Riedel.
But the palm oil plantations are tackling the rainforest. When he came to the TU Berlin in 2012, he discontinued his research on palm oil. "
Replacement found for plastic, cutting down rainforest - that cannot be the result of research," Riedel explains his decision.
Since 2017, Riedel has been expanding its PHA research with biogenic residues at the Department of Bioprocess Engineering, which is committed to the development of sustainable bioprocesses.
Source: TU Berlin