To solve this problem, we need to identify the equipment required for growing microbes on a large scale for industrial production of enzymes. Let's analyze each option:$\newline \bullet$Option 1: BOD incubator$\newline$ - A BOD (Biochemical Oxygen Demand) incubator is used to maintain temperature for the growth of microorganisms under controlled conditions, typically for small-scale laboratory experiments.$\newline$ - It is not suitable for large-scale industrial production.$\newline \bullet$Option 2: Sludge digester$\newline$ - A sludge digester is used in wastewater treatment to break down organic matter.$\newline$ - It is not specifically designed for enzyme production.$\newline \bullet$Option 3: Industrial oven$\newline$ - An industrial oven is used for baking, drying, or curing materials.$\newline$ - It is not used for growing microbes.$\newline \bullet$Option 4: Bioreactor$\newline$ - A bioreactor is a vessel or container in which biological reactions occur.$\newline$ - It is specifically designed for growing microorganisms on a large scale, making it ideal for industrial enzyme production.$\newline$Therefore, the correct equipment required for growing microbes on a large scale for industrial production of enzymes is a bioreactor.$\newline$This corresponds to Option 4.