Black Soldier Fly (BSF) presents an attractive ingredient for aquafeeds, but production costs are still too high. Abundant and low cost lignocellulosic sidestreams can be fed to BSF, but as cellulose is poorly digestible, feed conversion ratio (FCR) is poor. In this work Single Cell Protein (SCP) has been tested as a BSF feed ingredient with success. The SCP was derived from short-chain fatty acid (i.e. acetate), which has been demonstrated to be produced from cellulose. Specifically, a microbial bioconversion technology capable of converting cellulosic sidestreams into SCP intended for use in animal and aquafeed applications was presented at WAS 2022.
Bioreactor production of a high-density SCP produced from purified acetate was done, and prepared as a slurry for BSF feed additive, representing a novel feedstock for production of this promising aquafeed ingredient. It can be seen in that Figure 1 that while addition of untreated cellulose unfavourably raised the FCR, requiring 63% more feedstock at 30% inclusion, while SCP inclusion noticeably lowered the FCR, needing 27% less feedstock. Thus, this confirms that SCP is an improvement not only over cellulose, but also okara, a typical feedstock used for BSF. Currently efforts are underway to intensify the cellulosic bioconversion technology (Figure 2), and directly produce this SCP from cellulose and generate data for life-cycle analysis and costing. This approach can reduce costs for BSF and increase the application of in aquafeed with much improved sustainability and food security in Singapore and beyond.