Fatty acid methyl ester (FAME) & API 120 kits can be used for the identification

FAME is more expensive than BIOLOG, you need to buy GC chromotography system which is above 100K dollars,  and API kits have narrow identification range problem and can detect few species. Both of your suggestions are OK but in the same conditions, really BIOLOG is much better than both, 

API Kits are cheaper and provide satisfactory results. I have a system similar to BIOLOG, which is Bekten Dickinson (BD) make. Name is BBL CRYSTAL AUTOREADER. It work very same way as BIOLOG. But the problem I see with these instruments is the library they provide. In most cases the library is related to clinical specimens. If you are a person working on clinical samples, then your strains could be identified to a great extent with BIOLOG or BBL CRYSTAL AUTOREADER. In my case most of the strains are coming from environmental samples and the library provided by the supplier is not able to identify my cultures. 

16srRNA gene based identification is cheaper and more accurate.

FAME is also good, though expensive.

With some investment you can look MALDI TOF technology for identification. This is incredibly fast and accurate.

API kits are usually not realy accurate for environemental strains

Reza, were you trying to use Biolog Assay for bacterial or fungal isolates. 

Sorry, I am not really answering your question but trying to get to know if Biolog can be used for fungal isolates? 

Based on the BIOLOG brochure, it has capability for detection of some fungal species but the numbers are much lower than the bacterial.

Indeed, in my previous lab, i had never seen anybody using BIOLOG for fungi detection