Abstract

Two in-vitro experiments were conducted to evaluate the efficacy of Bacillus amyloliquefaciens culture broth (BA) on reduction of odorous gas emission from pig slurry. In experiment 1, the treatments included control (no spray), water spray, and spray with 1% (BA1), 5% (BA2), 10% (BA3) and 100% (BA4) BA. Each treatment was replicated three times. The only significant difference in NH₃ emission was observed at 48 h, when BA1, BA3 and BA4 showed significant reduction compared to the control. The H₂S emission was significantly reduced only at 3 h in response to treatments with BA compared to control. The SO₂ emissions from slurry were not affected by the treatments. The treatments of experiment 2 were: control (no spray), water spray, 10% BA spray one time/day and 10% BA spray one time/two day. The NH₃ emissions were significantly reduced in response to treatments with BA at day 4, 6 and 7 compared to the control. Significant reduction in H₂S emissions were observed from day 3 to 7 from the BA one time/day treated slurry compared to the control slurry. The SO₂ emissions did not differ among treatments, with the exception of a tendency to decline in response to treatment with BA one time/day at day 4 and 6. Overall, treatment with 10% BA one time/day was effective in reducing NH₃, H₂S, and SO₂ from pig slurry and can be used as manure additive.

Key words: Bacillus amyloliquefaciens, pig slurry, in-vitro fermentation, ammonia, sulfur dioxide, hydrogen sulfide.