A polyphasic taxonomic approach was used to characterize a presumably novel bacterium, designated strain CC-YTH191T, isolated from a fermented meal in Taiwan. Cells of strain CC-YTH191T were Gram-stain-negative aerobic rods, which grew at 15-40 �XC (optimal 25-30 �XC), pH 6.0-9.0 (optimal 7.0) and 1-2 % (w/v) NaCl (optimal 1 %). On the basis of 16S rRNA gene sequence analysis, strain CC-YTH191T appeared to belong to the genus Castellaniella, and was closely related to Castellaniella hirudinis (96.7 % similarity), Castellaniella ginsengisoli (96.7 %) and Castellaniella caeni (96.0 %), while with other related species it shared <96.0 % similarity. The major cellular fatty acids of the isolate were C16 : 0, C17 : 0cyclo, C14 : 0 3OH/C16 : 1iso I and C18 : 1�s7c/C18 : 1�s6c. The polar lipid profile contained diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylserine, three unidentified phospholipids, an unidentified aminolipid and an unidentified aminophospholpid. Putrescine was the predominant polyamine followed by spermidine. The DNA G+C content was 62.2 mol% and the predominant quinone system was ubiquinone 8 (Q-8). All these features confirmed the placement of the strain CC-YTH191T as a novel species within the genus Castellaniella, for which the name Castellaniella fermenti sp. nov. is proposed. The type strain is CC-YTH191T (=BCRC 81023T=JCM 31755T).