Table 2.

Characterization of Citrobacter youngae IITK SM2 isolated from As-polluted groundwater of Baikunthpur, India.

Characteristics	Strain IITK SM2
(a) General parameters
Gram staining test	Gram-negative
Shape	Rod
Cell size (μm)	0.3–0.6 × 2.2–3.4
Pigmentation (in Lysogeny agar plate)	Yellow
(b) Growth conditions
pH range	4–10
Optimum pH	7.25
Temperature range (°C)	15-45
Optimum temperature (°C)	30
NaCl tolerance (%; w/v)	0-6
Optimum NaCl tolerance (%; w/v)	1.5
(c) Minimum inhibitory concentration
Dissolved As(III)	1,100 mg L−1 (~14.7 mM)
Dissolved As(V)	32,000 mg L−1 (~427.1 mM)
Dissolved Fe(III)	1,000 mg L−1 (~17.9 mM)
Dissolved Mn(II)	5,000 mg L−1 (~91.0 mM)
Dissolved Cr(VI)	10 mg L−1 (~0.2 mM)
Dissolved Ba(II)	1100 mg L−1 (~14.7 mM)
Dissolved Zn(II)	250 mg L−1 (~3.8 mM)
(d) Antibiotic resistanceα
Ampicillin	100 μg L−1
Hygromycin	50 μg L−1
(e) Other specific parameters
Utilization of D-glucose	+
Catalase	+
Motility	+
Starch hydrolysis	—
G + C content (%)	51.7
Arsenic transformation capability	Reduces As(V) to As(III)

^α No resistance to kanamycin (50 μg L⁻¹), chloramphenicol (25 μg L⁻¹), ciprofloxacin (20 μg L⁻¹), gentamycin (10 μg L⁻¹), and streptomycin (50 μg L⁻¹) was observed.