Overview

Safety is always of massive essence to any work and any product. This year, we analyzed possible risks encountered during our whole project and list following three contents.

Safety in Laboratory

According to the government legislation and university’s regulations, we formed our specific lab safety rules as follows.

• Safety first, prevention first.
• The one in charge is the one to be responsible.
• PI should inform every student of detailed instructions.
• A duty system is needed and the last one to leave the lab should make sure all vents are shut down and windows are opened.
• People in the laboratory have to wear a lab coat, appropriate clothes, covered shoes and gloves.
• The opening date must be recorded for all enzymes, antibodies, and chemical reagents. Large-sized chemical reagents should have corresponding sample spoons. If sterile, please mark it.
• Toxic material must be locked at all time. Use log must be accurately recorded.
• During sterilization, the liquid shouldn’t exceed 2/3 of the volume; otherwise, it may cause gushing or burst, possibly contaminating surrounding samples or hurting people.
• Caps should be rescrewed when the sterilized liquid inside reaches room temperature.
• The central laboratory should be maintained at the appropriate temperature (25-28 degrees). Laboratories with the dedicated outdoor air system (DOAS) shouldn’t open windows. If ventilation, please watch out for insects and dust.
• All consumables and equipment should be labeled.

Safety in Design

According to our background research, bio-synthesis has advantages like yielding fewer intermediates and costing fewer chemicals over the traditional method. Fewer unpredictable substances mean lower potential toxicity and less contamination. And we’re obliged to firmly follow related instructions when we were disposing of requisite chemicals.

Safety in Implementation

In our project, only two strains of E. coli were selected and they both met the biological standard in iGEM. The DH5α strain was used for cloning and metabolites production; while the BL21 strain was used for protein expression. To extract our final product, retinol, we applied acetone extraction, which could kill bacteria - no live could survive. Besides, centrifugation was also used to extract intracellular retinol, which definitely pellet bacteria and only the supernatant was used for HPLC. Steps can be reviewed at our experiments page.

Despite this, there is still place for improvement. The fewer chemicals were used, the better for environment, maybe lower cost as well. As we described, one future direction is to use CRBP, which might be able to retinol outside cells. If the exported CRBP-retinol complex were soluble, we would no longer need chemical extraction for retinol production.