Valorization of waste streams, "From food by-products to worm biomass"

B. Laarhoven, H.J.H. Elissen, B.G. Temmink, C.J.N. Buisman

Research output: Chapter in Book/Report/Conference proceedingConference paperAcademic


A new technology is investigated to produce a high quality animal feed source by converting safe industrial food wastes into worm biomass. The freshwater worm Lumbriculus variegatus (common name: blackworm) has been selected for this purpose. This species can be used to reduce and concentrate municipal wastewater sludge and recover its nutrients. Its simple life cycle and high stress tolerance make this worm suitable for a controlled application. The worm’s macronutrient composition also makes it a promising aquaculture feed source. The levels of protein, lipid and sugar are in accordance with the general fish feed requirements. The goal is to develop an eco-effective bioreactor for the production of worms based on a low-grade waste stream. First, standardized growth experiments are performed to investigate the performance on different food wastes varying in macronutrient composition and origin (vegetable, bacterial and animal). For this purpose a suitable test setup was developed and in the meantime several successful tests with plant sources have been performed. Recent tests with wheat gluten and starch delivered more insight in the digestibility of protein and carbohydrates and resulting worm growth. Secondly, a prototype worm production reactor is designed, tested and optimized. The key element in this is the use of a carrier material which acts as a separation layer between the worm-feed compartment and the water column. In this concept, streams of worm feed, worms and worm feces can be separated. The challenge is to control the conditions for sustainable growth and efficient biomass production. To determine the efficiency of the reactor, mass flows for carbon and nitrogen are determined in combination with worm growth performances. In two years’ time, experiments with different food wastes of interest will result in various criteria for worm feed selection. Development of the reactor will mainly depend on the growth performance on a specific worm feed suitable for reactor application. The commercial success will largely depend on the acceptance of blackworms as a safe feed for cultured animals and the legalization of food waste products for worm feed application.
Original languageEnglish
Title of host publicationBiorefinery for food & fuel & materials
EditorsM. Bruins, T. van Boxtel
Place of PublicationWageningen
PublisherWageningen UR
ISBN (Print)9789461736239
Publication statusPublished - 2013
EventBiorefinery for Food & Fuel & Materials - Wageningen
Duration: 7 Apr 201310 Apr 2013


ConferenceBiorefinery for Food & Fuel & Materials


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