Option 1 states that microbes are used in sewage treatment plants, which is correct. Microbes, such as bacteria and protozoa, are used in the treatment of wastewater to break down organic matter and remove harmful pollutants.

Option 2 states that microbes are used in industrial fermenters for beverage production, which is also correct. Many beverages, such as beer, wine, and yogurt, are produced through the fermentation process, which involves the use of specific microbes, such as yeast and lactic acid bacteria.

Option 3 states that no antibiotic has been obtained from any microbe, which is incorrect. Antibiotics are medicines that inhibit the growth of or destroy bacteria. Many antibiotics, such as penicillin and streptomycin, are derived from microbial sources, particularly bacteria and fungi. These microbial products have been instrumental in the treatment of bacterial infections.

Option 4 states that microbes are used to obtain bioactive molecules for the treatment of diseases, which is correct. Microbes produce various bioactive molecules, such as enzymes, proteins, and secondary metabolites, that have therapeutic potential. These molecules have been used in the development of drugs and treatments for various diseases.

Therefore, the statement that is not correct is option 3, as antibiotics have indeed been obtained from microbes.