Advancing Sustainable Biomass Utilisation:
an interview with Asst. Prof. Iris Yu

In a recent interview we conducted with Dr. Yu, she shared insights into her research journey, the obstacles she has encountered, and the future prospects of biomass usage. She emphasised the importance of developing energy-efficient technologies and spoke about the potential of microwave-assisted processing in reshaping biomass conversion.

Dr. Yu’s studies aim to maximise the full potential of biomass via microwave-assisted processing, a technique that improves the efficiency of extracting valuable resources from organic feedstocks. The use of biomass can be an energy-intensive process, and conventional conversion methods, like anaerobic digestion and composting, primarily produce biogas and compost.

Dr. Yu’s approach offers a different pathway—using microwaves to directly heat the feedstock from within, minimising energy loss and allowing for the production of diverse bio-based products, including bio-oils, fuel chemicals, adhesives, and polymer precursors. During the interview, Dr. Yu explained why she chose microwave-assisted processing: “Microwave energy can be directly absorbed by the feedstock for internal heat generation, which lowers the chance of energy loss to the surroundings compared to conventional conductive heating.” She underscored that this method provides a promising alternative to traditional techniques and provides a broader spectrum of potential products.

By leveraging this method, Dr. Yu envisions a future in which biomass waste can be converted into valuable products, facilitating the transition toward a circular bioeconomy.

A recent direction of Dr. Yu’s work is the production of bio-oils, which hold promise as a sustainable substitute for energy and chemical applications. Nonetheless, incorporating bio-oils into current energy systems poses difficulties, including maintaining feedstock quality and cost-effective downstream processing.

Reflecting on these challenges, Dr. Yu noted, “Depending on the quality of the feedstock, bio-oils can still be far from being qualified as fuels, and a series of downstream processing steps will be needed, which may make the economics unfavorable.” She highlighted the importance of further research to determine the most appropriate feedstocks for energy applications and investigate other viable alternatives.

Dr. Yu also stressed that in urban environments like Singapore, where biomass waste comes in many forms, tailored approaches and a variety of technologies will be essential to effectively process varying waste compositions. “At the end of the day, society will need a diversity of technologies, not one single technology to handle all biomass waste,” she said.

While her work has significant implications for urban sustainability initiatives in Singapore, Dr. Yu also sees potential for her technology on a global scale. The ability to rapidly heat biomass and operate in a compact facility makes microwave-assisted processing particularly attractive for cities seeking sustainable waste management solutions.

Speaking about the impact of her technology, Dr. Yu shared, “Microwave-assisted processing has been suggested to significantly reduce the heating time and footprint requirement compared to conventional approaches. That leads to a more compact facility that suits places with urban settings.” This versatility enhances the importance of her research for densely populated areas worldwide.

Dr. Yu emphasises a key objective in her exploration of biomass utilisation—searching for the interaction between microwaves and biomass under particular circumstances to improve energy efficiency. “We found traces of how microwaves may interact with biomass under certain conditions, which may lead to energy savings,” she explained. This key insight is essential in showcasing the benefits of microwave technology compared to conventional heating techniques, which could revolutionise the wider field of biorefinery.

Looking ahead, Dr. Yu is investigating synergies between catalysts and microwaves to further enhance processing efficiency. Another exciting avenue involves integrating microwave treatment with other processes, such as developing sugar-rich hydrolysates suitable for microalgae cultivation, which can subsequently be collected for food and various other uses.