A Flexible System for Cultivation of Methanococcus and Other Formate-Utilizing Methanogens

Table 1

Most probable number dilution of M. maripaludis S2 in medium prepared by the rapid protocol^a.

	Inoculum (number of cells)	Positive number	Negative number
Three O2 removal cycles	1000	5	0
	100	5	0
	10	1	4
	1	1	4
	0.1	0	5
Control	1000	5	0
	100	5	0
	10	3	2
	1	1	4
	0.1	0	5

^aThree cycles of gas exchange used in preparation of the McF medium as described in Appendix B. The inoculum was serially diluted into 1000, 100, 10, 1, and 0.1 cells. Growth was monitored for 6 days. When the OD_600 nm was greater than 0.6, growth was defined as positive. Control medium was prepared in the anaerobic chamber as described in Appendix A.