The dynamic duo of bioremediation: A case study on the efficacy of Penicellium spp and Bacillus spp

Anaerobic digestion (AD) is a biological process in which microorganisms break down organic matter with biogas. It is a series of chemical reactions during which organic material is decomposed through the metabolic pathways of naturally occurring microorganisms in an oxygen-depleted environment. Recently, anaerobic digestion (AD) has been recognized as one of the best options for treating food waste/cattle rumen mixtures since it results in two valuable final products, biogas and digestate that may be utilized for electricity production and as soil fertilizer, respectively. However, putting the digestate directly into the soil may bring environmental concerns because they contain certain pathogens and heavy metals which could be detrimental to plant and human health when consumed as food. The experimental study carried out in this project has shown that heavy metals contained in food waste/cattle rumen mixtures can be removed using indigenous microbes (Bacillus spp and Penicellium spp). From the results of the experiment carried out, it was deduced that bioremediation is effective in removing heavy metals from AD sludge. This finding is of special importance because this means that digestate can be freely used as manure without worrying about plants absorbing dangerous heavy metals which are more than their allowable limit from the soil. The use of indigenous microbes is cheap since they are readily available in the digestate.