Microbial Biodiversity Isolated From Activated Sludge And Their Functions In The Degradation Of COD In The Waste Water From Potato Starch Industry

Water is a renewable resource and it is used for sustaining all life forms such as food production,economic development and for general well-being.Rapid population increase has resulted in the increase of water usage per capita in many areas of the world.Food processing industries,where there is use of large volumes of water has contributed to this challenge of water shortage.This is because,the food processing industry generate a lot of waste water during processing,resulting in the accumulation of high organic matter content in the form of COD,which is highly unsuitable to the environment and receiving water bodies when disposed without treatment.This has called for the use of more ecofriendly methods in waste water treatment,of which microorganisms play a key role in biological waste water treatment.This study aimed at isolating microorganisms from sludge samples that were used in treating Potato starch processing waste water and further using the isolates,in a fermentation process to ascertain their COD removal abilities.Potato processing waste water was prepared in the laboratory using potatoes that had been crushed with water in a blender and sieved to obtain the juice.The microorgan isms were isolated using culture technique under anaerobic and aerobic conditions and were preliminarily identified through biochemical characterization and by PCR,using 16 SrRNA sequencing.The microorganisms identified were made up both bacterial and fungal species including B.licheniformis,B.subtilis,B.haynesii,B.sonorensis,B.velezensis,Streptomyces echinatus,Pseudomonas fragi,Pseudomonas parafulva,Paenibacillus cookie strain,Cryptococcus sp.,Saccharomyces sp.,Candida sp.,Aspergillus sp.and Rhodotorula sp.Bacterial species were the dominant species making up 69 % of isolates while fungal species made up 31 %.49 % of the isolates belonged to the phylum Firmicutes which comprised all of the Bacillus species,making it the most dominant microbial species isolated from the sludge.The second dominant phylum was Ascomycota which contained 18 % of the isolates including Candida and Saccharomyces species.Phylum Proteobacteria(15 %)was the third dominant phylum and was made up of two species;Pseudomonas parafulva and Pseudomonas fragi.Other phyla included Actinobacteria,Basidiomycetes and Basidiomycota respectively.The microorganisms isolated from the activated sludge were tested for their ability to degrade COD in the waste water from t he Potato starch industry.This was done using a batch fermentation process involving each single microbial specie with Potato waste water as the sole substrate.The fermentation process was also carried out involving microbial consortia that was made up of a combination of the bacterial species,a combination of the fungal species and a mixed consortium that involved both fungal and bacterial species.Single microbial species which were used in the fermentation process achieved COD removal efficiency of between 79.30 % and 92.56 % after 72 hours.Saccharomyces,Candida and B.licheniformis achieved 92.56 %,91.54 % and 91.33 % COD removal respectively.The highest recorded COD removal efficiency during the fermentation process was however achieved using th ree different microbial consortia made of only bacterial species,only fungal species and a mixed consortium of both fungal and bacterial species.The highest COD removal of 95.97 % was achieved by the mixed consortium which was made up of both bacterial and fungal species.This was followed by a 91.56 % COD removal by the fungal consortium and an 88.95 % COD removal by the bacterial consortium.In this study it was observed that,the most effective way of COD removal from Potato starch processing waste wat er is through a combination of different microorganism especially a combination of both bacterial and fungal species for optimum results.