Utilization of Crude Glycerol as a Substrate for the Production of Rhamnolipid by Pseudomonas aeruginosa

Table 2

Characteristic absorption of rhamnolipid functional groups in infrared analysis.

Peak number	Characteristic absorption (cm^−1)	Functional group
1	3430	Strong and broad bands of the hydroxyl group free (-OH) stretch due to hydrogen bonding
2	2938	The aliphatic bonds CH3, CH2, and C-H stretching
3	2254	Unresolved
4	1736	Carbonyl (C=O) stretching (ester)
5	1629	Carbonyl (C=O) stretching (acidic)
6	1462	The aliphatic C-H bending
7	1421	The presence of carboxylic acid functional group in the molecule was confirmed by the bending of the hydroxyl (O-H) at 1421 cm^−1
8	1042	C-O-C stretching in the rhamnose
9	915	Fingerprint region and it is identical with that of the standard rhamnolipid
10	703
11	614
12	450