A profitable biorefinery solution to food waste

(01-04-2020) Members of the GREEN-CHEM network examined the techno-economic feasibility of a sophorolipid producing food waste biorefinery in Hong Kong.

The global demand for biobased surfactants, such as sophorolipids is on the rise. In megacities, such as Hong Kong, where there is a lot of food waste, sophorolipids can technically be made by fermenting the waste. However, is this biorefinery concept economically viable? Researchers from the GREEN-CHEM network, prof. Carol Lin (City University of Hong Kong), prof. Christian Stevens (Ghent Universityand prof. Wim Soetaert (Ghent University) examined the techno-economic feasibility of a sophorolipid producing food waste biorefinery in Hong Kong. They looked at several scenarios and what did they find? All scenarios were profitable and the best-case scenario only took a payback period of 2,5 years.  

A rising demand for biosurfactants 

Surfactants are tensio active compounds that are used to lower the surface tension of certain fluids. They are commonly used in the production of detergents, cosmetics and crop protection products. Due to stricter government regulations and an increased demand from consumers, a lot of companies in these sectors are making the switch from fossil fuel based compounds to biobased surfactants. One branch of biosurfactantsthe sophorolipids (SL’s), has some additional interesting properties. They are biodegradable and have low eco-toxicity, making them promising biosurfactants. 

Producing sophorolipids from food waste 

In Hong Kong a lot of food waste is generated, as around 1.45 kg of municipal solid waste (MWS) is generated per capita per day. Currently, most of the food waste gets dumped in landfills, which contributes to greenhouse gas emissions. The local government offers financial incentives to solve this waste problem. Therefore, researchers from the international GREEN-CHEM network, prof.  

Carol Lin (City University of Hong Kong), prof. Christian Stevens (Ghent Universityand prof. Wim Soetaert (Ghent University), investigated whether it would make sense from a techno-economic standpoint, to set up a food waste-based SL biorefinery in Hong Kong. They examined how fast and how much profit could be generated in different scenarios 

Is the biorefinery economically viable?  

Several scenarios were analyzed to examine the economic viability of this food waste biorefinery. “We found that every scenario was profitable. However, the third scenario yielded the most profit”, says prof. Chris Stevens from the UGent team. In this scenario, equipment was bought close by from Mainland China and the final product were SL crystals, which are higher in value, as opposed to SL syrup. An economic analysis revealed a 44% return on investment and a 2.3-year payback period. However, replicating the biorefinery plant in other cities might not be equally profitable without similar financial incentives provided by the Hong Kong government”, prof. Christian Stevens adds as a word of caution 


“We plan to submit a European Commission project with the objective to create new integrated value chains. Regional and sustainable biomass feedstocks will be converted into novel microbial biosurfactants. The success of this joint EU project would provide the backbone for a European flagship biosurfactant product biorefinery plant.”, mentions prof. Carol Lin.

“Moreover, in our laboratory, we are currently experimenting with the use of SLs in several more high-end applications. For example, we are attempting to combine both the surfactant and antimicrobial properties into one product. A derivative could be implemented in detergents. If we succeedSL’s could generate more revenue in the near future. This means biorefineries of this kind could become more profitable around the world.”, concluded by prof. Chris Stevens.