Effective production of bacterial cellulose using acidic dairy industry by-products and agro wastes

Abstract

The study aimed to evaluate the production of bacterial cellulose (BC) by specialized bacteria using raw acidic dairy wastewater and milk whey as well as evaluating the bioremediation ability of the tested bacteria for the purification of polluted wastewater. Raw dairy wastewater samples were collected from Milk Factory in Alexandria Governorate, Egypt. Three bacterial isolates were isolated from spoiled Tomato (T0) and Pomegranate (R01 &R02), and investigated as free-living and fixed individual and mixed cultures in batch mode bioassays. BC was extracted, determined and characterized. T0, R01 &R02 were molecularly identified as Bacillus velezensis strain FZB42 (T0), Klebsiella quasipneumoniae subsp. similipneumoniae strain 07A044 (R01 and R02). T0 achieved the maximum BC yield of 31.9 g/L compared to 13.18 g/L produced by the standard synthetic Hestrin-Schramm (HS) medium. It also showed the highest growth stimulation (7.78-fold higher density than its initial density). All strains showed the highest removals of the TSS, TDS, COD and BOD reaching residual concentrations (RCs) of 12, 2050, 75 and 25 mg/L, respectively, all of which were much lower levels than their limits stated by environmental laws (60, 5000, 80 and 60 mg/L, respectively). BC production by the tested bacteria grown in the raw dairy wastewater is considered an excellent achievement, feasible and value-added technology. The tested bacteria are remarkably efficient for the treatment of dairy effluents in a very short time. Therefore, it is highly recommended to use the proposed bacterial system for feasible BC production and purification of highly polluted dairy wastewater.