Table 3.

Effect of precursor substrates on polyhydroxyalkanoates production by Bacillus spp. from pea-shell slurry^a

Precursor substrate added to feed	Substrate (%)	DCM (mg/l)	Polyhydroxyalkanoates
			mg/l	% DCM	3HB	3HV
					mol%
Bacillus co-culture 5BC1
Controlb	0.0	3,460	650	18.8	100	0
Sodium propionate	0.5	3,850	650	16.9	87	13
	1.0	3,800	1,050	27.6	93	7
	2.0	3,600	900	25.0	93	7
Valeric acid	0.5	2,760	640	23.2	90	10
	1.0	2,340	520	22.2	93	7
	2.0	1,810	300	16.6	93	7
Bacillus cereus EGU44
Control	0.0	4,000	1,200	30.0	100	0
Sodium propionate	0.5	3,950	855	21.6	89	11
	1.0	4,000	660	16.5	84	16
	2.0	3,650	610	16.7	85	15
Valeric acid	0.5	3,135	525	16.7	83	17
	1.0	3,080	720	23.4	90	10
	2.0	2,860	720	24.5	90	10

Values are based on three sets of experiments. Standard deviation was less than 5 %

DCM dry cell mass, 3HB 3-hydroxybutyrate, 3HV 3-hydroxyvalerate

^aPea-shell slurry (2 % TS) pretreated for 2 days with MHC2 and supplemented with 0.5 % (w/v) glucose

^bNo precursor substrate added