Powdered agar is actually agar that is ground into powder during the refining process, which is for the convenience of transportation, preservation, and weighing of agar, and is generally used to configure agar for microbiology, biochemistry, or other experiments that use agar.
Nutritional agar is the use of agar powder and some other nutrients through a certain proportion of the configuration of a solid agar medium for the growth of microorganisms, microorganisms that do not require high nutritional growth. Because it is not selective for bacteria, it is generally not used for bacterial identification.