Isolation and characterization of onion degrading bacteria from onion waste produced in South Buenos Aires province, Argentina

Abstract

Onion production in Argentina generates a significant amount of waste. Finding an effective method to recycle it is a matter of environmental concern. Among organic waste reuse techniques, anaerobic digestion could be a valuable alternative to current practices. Substrate inoculation with appropriate bacterial strains enhances the rate-limiting step (hydrolysis) of anaerobic digestion of biomass wastes. Selection of indigenous bacteria with the ability to degrade onion waste could be a good approach to find a suitable bioaugmentation or pretreatment agent. We isolated bacterial strains from onion waste in different degradation stages and from different localities. In order to characterize and select the best candidates, we analyzed the growth patterns of the isolates in a medium prepared with onion juice as the main source of nutrients and we evaluated carbon source utilization. Nine strains were selected to test their ability to grow using onion tissue and the five most remarkable ones were identified by 16S rRNA gene sequencing. Strains belonged to the genera Pseudoxanthomonas, Bacillus, Micrococcus and Pseudomonas. Two strains, Bacillus subtilis subsp. subtillis MB2-62 and Pseudomonas poae VE-74 have characteristics that make them promising candidates for bioaugmentation or pretreatment purposes.

Caproicibacter fermentans gen. nov., sp. nov., a new caproate-producing bacterium and emended description of the genus Caproiciproducens

“…W14A [36], Clostridium sp. MB2-A37 [37], Cp. galactitolivorans BS-1 T [3] and ‘ Ruminococcaceae bacterium CPB6’ [19].…”

Benefits of Pseudomonas poae s61 on Astragalus mongholicus growth and bioactive compound accumulation under drought stress

“…A novel lipopeptide poaeamide has been identified and is responsible for pathogen suppression and root colonization (Zachow et al 2015). In addition, the species can be used as promising candidates for bioaugmentation (Rinland and Gomez 2015) and a bacterial consortium including P. poae could degrade cooking oil in wastewater (Nzila et al 2017). However, no reports are available on the performance of P. poae under other stress conditions generated by environmental factors in medical plants.…”

Bacillus subtilis ALBA01 can mitigate onion pink root symptoms caused by Setophoma terrestris

“…Onion ( Allium cepa L.) is an important vegetable crop with a worldwide production of approximately 73 million tons per year, 8% of which is lost because of disease constraints (Rinland et al 2015). In Argentina, onion production is very important, in terms of quality and quantity, being the main producer country and exporter of dehydrated onions of Latin America (SENASA 2014).…”