After you successfully designed a pathway and implemented it in E. coli for production of the biofuel molecule, 1-butanol, you noticed that the production of the desired metabolite is not ideal. What are the possible strategies that you can use to optimise the pathway productivity? 1. Increase the flux of glucose by the removal of a negative regulator of the glucose transporter. 2. Completely knockout or delete the fatty acid biosynthesis pathway that competes for the acetyl-CoA precursor. 3. Fine-tuning of expression levels of the enzymes in the synthesis of 1-butanol to avoid the accumulation of intermediates. 4. Increase or balance the supply of the NADPH cofactor by upregulating the pentose phosphate pathway. 5. Only choices (1), (3) and (4) are correct. 6. Only choices (1) and (3) are correct. 7. All choices are correct