Enhancement of pyrene degradation efficacy of Synechocystis sp., by construction of an artificial microalgal-bacterial consortium

Figures & data

Table 1. Selected doses of PYR to Synechocystis sp. and consortium JP-NK

PYR treatment	Lower to LC50 concentration (mg/L)	LC50 concentration (mg/L)	Higher to LC50 concentration (mg/L)
Synechocystis sp.	1.5	3	6
Consortium JPNKA7 (Synechocystis sp. + Bacillus benzoevorans)	20	40	80
Consortium JPNKB2 (Synechocystis sp. + Pseudomonas indoxyladons)	35	70	140
Consortium JPNKB2A7 (Synechocystis sp.+ Pseudomonas indoxyladons + Bacillus benzoevorans)	50	100	200

Table 2. Tolerance level of isolated bacterial strains to PYR at 37°C temperature 150 rpm shaking condition after 48 h

S. No.	Isolated bacteria	PYR concentration (mg/L)
		25	50	75	100	125	150	200
1	AX1	+++	+++	++	–	–	–	–
2	AX2	++++	+++	++++++	+++	++++	–	–
3	AX3	++++	+++	++	–	–	–	–
4	AX5	++++	+++	++	–	–	–	–
5	AX7	++++	++++	++++	++++	+++	+++	+
6	AX8	++++	++++	++	–	–	–	–
7	BX2	++++	+++++	++++	++++	++++	+++	+++
8	BX3	++++	++++	++	–	++	–	–
9	BX4	++++	++++	+++	++	–	–	–
10	BX6	++++	+++	+++	+++	–	–	–
11	BX9	++++	++++	++++	++++	+++	+++	+
12	BX11	+++	+++	+	–	–	–	–
13	BX16	+++	++	–	–	–	–	–
14	BX17	++++	++++	++	–	–	–	–
15	BX18	++	+++	–	–	–	–	–
16	BX22	++	–	–	–	–	–	–

Notes: ++++ denotes very high growth, +++ denotes high growth, ++ denotes moderate growth, + denotes slow growth and – denotes no growth. AX strains were isolated from site-A and BX strains isolated from site-B.

Figure 1. Degradation of selected bacterial isolates to 100 mg/L of PYR.

Figure 2. Percent reduction in Chl-a (chlorophyll-a) content with different concentrations of PYR Synechocystis sp. and Con (consortium) JP-NK.

Figure 3. Percent degradation of PYR by Synechocystis sp. and Con (consortium) JP-NK.

Table 3. Specific degradation rate constants (k) in the PYR-treated organisms after 16 days

PYR treatment (mg/L)
Synechocystis sp.			Cons. JP-NKA7			Cons. JP-NKB2			Cons. JP-NKA7B2
1.5	3.0	6.0	20	40	80	35	70	140	50	100	200
0.028 (0.691)	0.016 (0.767)	0.011 (0.765)	0.075 (0.800)	0.050 (0.781)	0.043 (0.775)	0.135 (0.711)	0.100 (0.801)	0.078 (0.799)	0.174 (0.997)	0.128 (0.803)	0.0961 (0.799)

Notes: k (day⁻¹) represents degradation rate constant, and R² is the correlation coefficient obtained for the regression analyses (R² in parenthesis).

Figure 4a. Growth of Synechocystis sp. in terms of chlorophyll-a on xenobiotic compounds.

Figure 4b. Growth of consortium JP-NKA7 in terms of chlorophyll-a on xenobiotic compounds.

Figure 4c. Growth of consortium JP-NKB2 (in terms of chlorophyll-a) on xenobiotic compounds.

Figure 4d. Growth of consortium JP-NKA7B2 (in terms of chlorophyll-a) on xenobiotic compounds.