Bacillus velezensis Biotechnology GABA HS-SPME-GC/MS Indonesian fermented foods Kluyveromyces marxianus L. plantarum PAH Penicillium chrysogenum S. cerevisiae Streptomyces clavuligerus Technology: general issues aerobic stability bacterial community biocontrol bioreactor calibration carboxylate platform carboxylic acids cell cultivation cell morphology chain elongation children clavulanic acid dextrin double fortification ethanol production feast/famine conditions fed-batch at cell level (FBC) fermentation process