From grain processing waste to high-value products

​Cereal wastes such as rice bran and cereal dust are valuable yet underutilised by-products of grain processing.

Swinburne University of Technology researchers have now developed a process that converts this waste from the cereal industry into high-value bacterial cellulose (BC) — a material that can then be used in products such as medical dressings, food packaging and even parts of electronics.

The technique, shown in their study published in Foods, uses a natural fermentation process to transform rice bran and cereal dust into BC. The researchers claim the technique could be used to reduce production costs by up to 90% while maintaining quality, in an industry worth over $750m globally.

Lead researcher Dr Vito Butardo Jr said this research could divert thousands of tonnes of agricultural waste from landfill while also addressing the high cost of producing bacterial cellulose using conventional methods.

“Despite containing valuable nutrients, excess rice bran and cereal dust typically end up as waste or as low-value animal feed. Our innovative process creates a sustainable circular economy solution that reduces waste and saves money,” Butardo said.

“Most importantly, extensive testing confirmed that our waste-derived bacterial cellulose maintains the same high-quality characteristics as cellulose produced from expensive conventional media.”

The Swinburne team used stabilised rice bran from SunRice and cereal dust from Rex James Stockfeed Ltd to employ a natural two-step fermentation process where common food-grade fungi Rhizopus oligosporus (also used in tempeh production) break down the complex fibrous structure of the cereal waste through solid-state fermentation.

This process makes nutrients more accessible for the second stage, where bacteria convert these nutrients into pure bacterial cellulose.

“Using rice bran pre-treated with Rhizopus oligosporus, we achieved a 22% increase in bacterial cellulose yield compared to untreated materials,” Butardo explained.

The research is said to have significant environmental and commercial implications for industries seeking sustainable alternatives to synthetic products.

The global bacterial cellulose market is experiencing rapid growth, projected to reach $1.5 trillion by 2028 (US$950 million) with applications spanning wound dressings, artificial skin, water filtration membranes, food packaging and components for flexible electronics.

Butardo now hopes to scale up the technology. 

Image credit: iStock.com/Alex Liew