Improvement of mealworm digestion towards spent coffee grounds with assistance of feeding-inoculation

• Main Author: Mahesh Krishnan Shyamkumar
• Other Authors: Loo Say Chye Joachim
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2023
• Subjects: Engineering::Materials
• Online Access: https://hdl.handle.net/10356/166572
• Institution: Nanyang Technological University

Coffee is one of the most highly consumed products in the world. Accordingly, there is an enormous amount of residues that are formed during the making of coffee. Spent coffee grounds (SCG) make up a majority of this residue with around 600g of SCG being formed from every kilogram of coffee beans used. Despite being abundant in organic resources such as saccharides and proteins, a significant portion of SCGs are discarded every year. Thus, more methods to utilise this untapped reservoir of energy is required. A method that will be explored in this experiment is the use of SCG as a potential source of nutrition for mealworms due to its high energy content, which can in turn be used for feeding livestock such as fish. Yellow mealworms have a broad diet and thus are good candidates in attempting to digest SCG. However, SCG possesses antimicrobial properties, causing it to be not digestible to mealworms. Thus, the aim of this experiment was to attempt to improve the efficiency in the digestibility of the SCG. This was done by inoculating the SCG feedstock using bacterial strains from the gut of the mealworm that are capable of degrading SCG, which should improve the digestibility of the SCG by pre-digestion of the SCG before consumption, as well as delivering more of said bacterial colonies into the gut of the mealworm to further enhance their ability to digest SCG. The results of the study show that the feeding inoculation was successful to a certain degree, with the mealworms fed the inoculated SCG feedstock exhibiting higher levels of protein as well as showing higher levels of SCG degrading bacteria in the gut of the mealworms. However, as the survival rate, change in biomass as well as fat levels of the mealworms in the inoculated category were similar to the ones in the untreated SCG category, further experimentation will be required to be carried out to reveal how inoculated strains affect body compositions of mealworms.