Table 3.

Various functional groups involved in chromium (VI) binding by different microorganisms

S. No.	Microorganisms	Functional groups	References
1.	Bacillus marisflavi and Arthrobacter sp	-OH, -NH acetamido group, free phosphates, phosphate groups, -CN	[34,110]
2.	Pseudomonas aeruginosa Rb-1 and Ochrobactrum intermedium Rb-2	-OH, -NH, S-, -C-C- and C-Cl,- carboxylic group,	[96,111]
3.	Streptomyces werraensis LD22	O–H or N–H, C–H, C–O –	[97,112]
4.	Aspergillus foetidus	C = O, C-Cl, PO4 −3 amine, N = C = S, OH, C-O	[98,113]
5.	Pleurotus ostreatus	NH and COOH	[99,114]
6.	Aspergillus Niger	-COOH, -OH, -NH2	[100,115]
7.	Klebsiella sp.	-NH2, O-H, -CONH-, -COOH, C = C, -CH2	[87,100]
8.	Halomonas sp. DK4	–OH, – CH2, N-H, P–O–C, C = O	[101,116]
9.	Scenedesmus sp	N-H, O-H, C-H, -COOH, C-F, C-Cl, C-Br, C-O	[31,117]
10.	Chlorella miniata	O-H and N-H, C-H, -CH3, COO-, P = O, C-O –	[102,118]
11.	Arthrinium malaysianum	–OH, C–O, C = O, – NO2, CxOH	[103,119]
12.	Pleurotus ostreatus	NH and COOH-	[99,114]
13.	Aspergillus Niger	-COOH, -OH, -NH2	[100,115]