The efficiency of potential food waste-degrading bacteria under harsh conditions.

AIMS: Investigate the impact of highly adapted bacterial strains and their ability in waste degradation under a wide range of temperatures. METHODS AND RESULTS: Bacteria isolated from soil and food waste were grown in various media under fluctuated temperatures. After screening for organic compound degradation, the seven strongest bacterial strains have been selected for further experiments. Their enzyme activities were expressed in terms of the size of the hydrolysis zone in a wide temperature range of 2·5-70°C. The enzyme production assay was carried out for each protease, cellulase and amylase. The waste degradation was determined with a maximum 80% decrease in the volume of food waste in 21 days compared to the control in lab scale with enriched bacterial cultures and soil bacteria as additives at room temperature around 18-20°C. CONCLUSION: These seven bacteria are promising candidates for food waste biodegradation in composting especially in the winter without heating expense for maintaining ambient temperature. SIGNIFICANCE AND IMPACT OF THE STUDY: It is necessary to coax the uncultured bacteria from the various environments into the laboratory for investigating their valuable functions. Herein, using enrichment culture of consortium and additive of soil has illustrated the significant mean in food waste degradation.

Brevundimonas albigilva sp. nov., isolated from forest soil.

Strain NHI-13T, a Gram-stain-negative, aerobic and short rod-shaped bacterium, was isolated from forest soil at Kyonggi University in Suwon, South Korea. It grew optimally in R2A medium, at 20-30 °C, in the presence of 0-4 % NaCl. Colonies resulting from incubation of the strain on agar plates for 2 days were circular, raised, translucent, viscous and whitish-yellow, with entire margins. This strain exhibited high catalase activity but was negative for oxidase. 16S rRNA gene sequence analysis showed that strain NHI-13T formed a coherent cluster with members of the genus Brevundimonas. Its similarities were 98.0 % with Brevundimonas aurantiaca DSM 4731T, 97.9 % with Brevundimonas vesicularis LMG 2350T, 97.6 % with Brevundimonas intermedia ATCC 15262T, 97.5 % with Brevundimonas nasdae GTC 1043T, 97.1 % with 'Brevundimonas olei' MJ15, 97.1 % with Brevundimonas mediterranea V4.BO.10T and 97.0 % with Brevundimonas poindexterae FWC40T. The major cellular fatty acids were summed feature 8 (C18 : 1ω7c/C18 : 1ω6c), C16 : 0 and 11-methyl C18 : 1ω7c. The DNA G+C content was 63 mol%. The predominant quinone was ubiquinone Q-10. The polar lipid profile contained 1,2-di-O-acyl-3-O-α-d-glycopyranuronosyl glycerol, 1,2-di-O-acyl-3-O-α-d-glycopyranosyl glycerol, 1,2-di-O-acyl-3-O-[d-glycopyranosyl (1 → 4)-α-d-glucopyranuronosyl] glycerols, phosphatidylglycerol, 1,2-diacyl-3- O-(6'-phosphatidyl-α-d-glucopyranosyl) glycerol and other unknown lipids. The DNA relatedness of strain NHI-13T with its reference strains was in the range of 43-56 %. On the basis of its phenotypic, genotypic, chemotaxonomic and phylogenetic distinctiveness, strain NHI-13T is suggested to be a representative of a novel species, belonging to the genus Brevundimonas. Therefore, the name Brevundimonas albigilva. sp. nov. is proposed, with the type strain being NHI-13T ( = KEME 9005-016T = KACC 18249T = JCM 30385T).