Biodegradable plastics made from sewage sludge

The researchers report in American Chemical Society (ACS) Omega that the bacterium Zobellella denitrificans ZD1 can consume sludge and wastewater to produce polyhydroxybutyrate, a type of biopolymer that can be used instead of petroleum-based plastics.

Sewage sludge could fuel eco-friendly production of biosolids bricks

The researchers believe Zobellella denitrificans ZD1 offers a way to cut down upstream costs for bioplastics manufacturing, marking a step toward making them more competitively priced.

"The price of raw materials to cultivate biopolymer-producing bacteria accounts for 25-45 per cent of the total production cost of manufacturing bioplastics. Certainly, this cost can be greatly reduced if we can tap into an alternate resource that is cheaper and readily obtainable," said Kung-Hui (Bella) Chu, professor in the Zachry Department of Civil and Environmental Engineering. "We have demonstrated a potential way to use municipal wastewater-activated sludge and agri- and aqua-culture industrial wastewater to make biodegradable plastics. Furthermore, the bacterial strain does not require elaborate sterilisation processes to prevent contamination from other microbes, further cutting down operating and production costs of bioplastics."