Which of the following statements is incorrect?

The correct answer is Option (1) → The yeast used in making bread and beverages is a prokaryotic bacterium.

The question asks for the wrong statement. Three of the options are uses of microbes and microbial products given in the book. The odd one describes yeast wrongly: yeast is a fungus, which is a eukaryote, not a bacterium.

Option (1) The yeast used in making bread and beverages is a prokaryotic bacterium. — The incorrect statement. The yeast used for bread and beverages is Saccharomyces cerevisiae (baker’s or brewer’s yeast). It is a eukaryotic fungus with a true nucleus, so calling it a prokaryotic bacterium is wrong.

Option (2) Streptokinase is produced by Streptococcus, modified by genetic engineering, and used as a clot buster. — A correct statement. Streptokinase is made by the bacterium Streptococcus, modified by genetic engineering and used as a ‘clot buster’ to remove clots from blood vessels after a heart attack.

Option (3) Lipases are added to detergent for removing oily stains from laundry. — A correct statement. Lipases break down fats, so they are added to detergents to remove oily stains from laundry.

Option (4) Pectinases are used in the clarification of bottled fruit juices. — A correct statement. Bottled fruit juices are clearer than home-made ones because they are clarified by pectinases and proteases.

NCERT Extract:
Microbes in Household Products – “… Similarly the dough, which is used for making bread, is fermented using baker’s yeast (Saccharomyces cerevisiae).”
Chemicals, Enzymes and Other Bioactive Molecules – “… Lipases are used in detergent formulations and are helpful in removing oily stains from the laundry. You must have noticed that bottled fruit juices bought from the market are clearer as compared to those made at home. This is because the bottled juices are clarified by the use of pectinases and proteases. Streptokinase produced by the bacterium Streptococcus and modified by genetic engineering is used as a ‘clot buster’ for removing clots from the blood vessels of patients who have undergone myocardial infarction leading to heart attack.”