Upcycling of the industrial waste as a sustainable source of axenic fungal strain (Aspergillus oryzae) for scale up enzymatic production with kinetic analysis and Box–Behnken design application

Abstract

Abstract The utilization of industrial waste for valuable product synthesis is essential for mitigating the environmental impact of climate change and managing waste disposal challenges. Industrial waste is always a big challenge for global warming. In this study, a novel fungus strain was isolated, and identified as Aspergillus oryzae (AKMS), from the oily surface of industrial effluent from an oil industry. Submerged fermentation was exploited to achieve maximum lipases production. A sequence of batch experiments was performed, altering five primary components: sucrose (for carbon), molasses (constituting nutrient mix), yeast extract (as nitrogen supply), sunflower oil (used as an activating agent), and Tween-80 (functioning as an emulsifying agent). These elements are recognized for their substantial impact on the proliferation of microorganisms and, consequently, the synthesis of lipases. The maximum lipase activity for each ingredient was determined, with sucrose showing 2.4 ± 0.539 U/mL at 0.15 g/L, molasses at 1.499 ± 0.291 U/mL at 0.25 g/L, Tween 80 % at 3.33 ± 0.484 U/mL at 0.25 g/L, sunflower oil at 7.49 ± 0.282 U/mL at 1 % v/v, and yeast extract at 4.165 ± 0.841 U/mL at 0.075 % v/v. The optimization of the lipase production and activity was done by using RSM (Box–Behnken design) with the 41st run yielding the maximum activity of 9 U/mL, while the 25th run showed the minimum activity of 4 U/mL, enzyme estimation (U/mL and U/g), glucose (g/L), and dry cell mass estimation (g/L) were monitored up to 120 h of fermentation in a custom-made fermenter with a working volume of 7 L. The highest production of extracellular and intracellular lipases (27.4 ± 0.378 U/mL and 25.4 ± 0.208 U/g, respectively) was observed at the 40 h interval, with the highest value of dry cell mass at 20 g/L. Glucose concentration initially peaked and subsequently decreased over time. A. oryzae exhibited the capability to produce triacyl glycerol acyl hydrolases, demonstrating its potential significance in biotechnological applications. These novel findings shed light on the efficient utilization of oil industry waste soil for isolation of microorganism for sustainable lipase production and highlight the biotechnological promise of the novel isolated fungal strain, which was reported first time in this study.