Effect of bacterial co-culture and organic amendments on the bioremediation of hydrocarbons in a soil contaminated with spent engine oil oleh Adeniyi Olarewaju Adeleye, Mohammed Bello Yerima, Micheal Edem Nkereuwem, Victor Odiamehi Onokebhagbe, Gimba Peter Shiaka, Afeez Oladeji Amoo, Catherine Iyabo Asaju, Babangida Yalwaji, Saheed Mohammed Ishaq