Table 1.

Sample load in µL on the agarose gel for visualization of crude DNA extracts.

Extraction protocol according to first author		Origin of samples
		Activated sludge	Havel River sediment	Anaerobic digestion sludge	Nitrifying sludge
A	Bourrain	4	15	5	8
B	Gabor harsh	2	8	5	8
C	Garbor soft	2	8	5	15
D	Shan	4	12	10	20
E	Orsini/Spica	4	8	6	15
F	Singka	4	12	15	15
G	Soya method	1	20	3	15
H	Tabatabaei	2	10	12	8
I	Tresse	1	6	6	10
J	Wilson	2	4	12	8