Microbial Diversity and Digestive Enzyme Activities in the Gut of Various Species of Earthworms

Ammeer, Umme Kauthar Aneesah (2021) Microbial Diversity and Digestive Enzyme Activities in the Gut of Various Species of Earthworms. Final Year Project (Bachelor), Tunku Abdul Rahman University College.

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Abstract

Solid waste management is a worldwide issue that has become increasingly complicated as the world's population, industrialization, and lifestyles start changing. The conversion of industrial sludges into vermicompost can be beneficial as the waste can be converted into a valuable product, and the waste accumulation can be significantly reduced. The epigeic earthworms Eudrilus eugeniae, Eisenia foetida, Perionyx ceylanensis, Perionyx excavatus and Lampito mauritii were used to recycle paper waste, press mud, and cow dung through vermicomposting. The bacterial content of the earthworms' guts and vermicomposts, as well as their enzymatic activity, were studied. This study clearly demonstrates that vermicomposting cow dung, press mud, and paper sludge can be of dual benefit based on locations, particularly in the agricultural sector. Vermicomposting affects decomposition by hastening the stabilisation of organic matter and improving the soil's physical and biochemical properties. E. eugeniae was the most studies species and showed commendable results in terms of enzyme activity and bacterial count. For most vermicomposting method cow dung was extensively uses as substrate with 950x106 CFUg-1 observed in the gut of E. eugeniae, demonstrating its benefit to plants in their early stages of development. Another possible substrate is press mud, which has been shown to cause both a high gut count of 1167x106 CFUg-1 and a high gut enzyme activity of 42.66 mg/g of cellulase and 0.549 units/mg of Nitrate reductase when tested in the gut and vermicasts of earthworms. It was found that cow dung alone as a substrate worked well but when combined with other substrates like press mud and paper sludge yielded 378.2x106 CFUg-1 in some species. Although earthworms can speed up the initial decomposition of organic residue, several studies have shown that they can also help preserve it by integrating and retaining soil organic matter in their casts. With the possibility of converting wastes into more valuable products, vermicomposting is beneficial and can greatly help in covering economical losses that are caused by excessive waste accumulation that have high maintenance costs to an economy.