Isolation and selection of certain strains of microorganisms capable of hydrogen sulfide gas reduction from Swiftlet droppings

Abstract

Hydrogen sulfide gas is one of the toxic gases, has an unpleasant odour and is created during the decomposition of Swiftlet's nest faeces. In a Swiftlet's nest house, the increased levels of hydrogen sulfide will irritate the mucous membranes and damage the Swiftlet's senses. Therefore, it seriously affects the quality and output of a Swiftlet's nest. This study aims to isolate and select sulfur-reducing bacteria strains from Swiftlet faeces to reduce the impact of hydrogen sulfide gas on Swiftlet nests, humans, and the environment. With methods of isolating, selecting, and evaluating the sulfide-degrading ability of bacterial strains on minimal mineral medium (MM) from Swiftlet's nest faecal samples, the study has isolated 6 bacterial strains capable of degrading sulfide and identified strain AG2.3-S as the Micrococcus luteus species with the highest sulfide absorption ability, reaching 84% efficiency (from 200 to 32.0 mg/l) after 5 survey days. Micrococcus luteus bacteria concentration at 109 CFU/g can reduce hydrogen sulfide gas content (≤5 mg/l) in Swiftlet's nest faeces within seven days of treatment. The results of the study are the basis for forming microbial products to reduce hydrogen sulfide gas in Swiftlet nest houses and poultry farms.