Abstract
It is vital to ensure the safe disposal of organic residues, in particular due to the accumulation of organic waste contributing to environmental pollution, while also spreading epidemics, diseases and unpleasant odours, and releasing ammonia and other harmful gases. This has led researchers to consider a number of direct applications for organic waste, including biotechnological applications. These are widely known to offer ecological and economic benefits, including: (1) limiting fossil fuel consumption; (2) reducing polluting emissions; (3) facilitating the production of cost-effective raw materials; and (4) developing a suitable substrate for a variety of microorganisms. Sustainable bioenergy (i.e. bio-gas, bio-diesel and bio-butanol) is an end product of biotechnology and an attractive solution for the disposal of organic feedstock. Carbohydrates form the primary ingredient of the organic fraction, while the majority of such polymers are readily microbial degradable. This review therefore focuses on isolated strains of different microorganisms with the capacity to utilise one or more forms of organic waste as a sole carbon source from different residue, in order to produce biofuel as its final products. The isolation involves: (1) the collection of random samples from soil exposed to organic waste; (2) purification of the microbial isolates; and (3) a comparison of the capabilities of the microbes, in order to identify the most valuable strain.