Which organisms used for SCP may contain significant amounts of nitrogen in an unavailable form?

Which of the following is the source of pro-vitamin A?

The first stage in the screening of microorganisms for industrial applications is

The first commercially produced plant secondary metabolite using bioreactor technology is

"Substances added prior to or simultaneously with the fermentation which are incorporated without any major change into the molecule of the fermentation product and which generally cause increases in the yield or improves the quality of the product" can be referred to as