Comparison of various microbial inocula for the efficient anaerobic digestion of Laminaria hyperborea

BMC Biotechnology

Table 3 Weekly protocol for the semi-continuous fermentation of L. hyperborea in single-stage fermenters

Treatment			Day
	1*	2	3	4	5	6	7
	Mon	Tue	Wed	Thu	Fri	Sat	Sun
Volume of leachate removed (mL)	200	0	60	0	60	0	0
Volume of leachate removed (mL)	(140 mL returned)	0	60	0	60	0	0
Volume of 20% wet W/V L. hyperborea added	10	10	10	10	20	0	0
Volume of PBS added	50	0	50	0	40	0	0
Seaweed removed	yes	no	no	no	no	no	no

*From week two onwards, on day 1 of each week the contents of each fermenter were removed to a sterile plastic pot. A 140 mL volume of the leachate of each fermenter was poured back into the fermenter, 10 mL of L. hyperborea seaweed was added and the fermenter volume was made up to 200 mL with PBS. In this manner the fermenter volume was maintained at 200 mL; seaweed was added daily and leachate was removed every second day. The residual seaweed was dried for estimation of residual total solids, then ash and volatile solids (see Methods section). This semi-continuous system was designed to reduce acidity and product feedback inhibition from volatile fatty acids, whilst having a long enough hydraulic retention time to allow maintenance of slow growing and acid sensitive methanogens and also allow digestion of seaweed to occur and was similar to the phase 1 system of a two-stage semi-continuous system adopted by Vergara-Fernández et al.[7].

ISSN: 1472-6750