Insights into effects of salt stress on the oil-degradation capacity, cell response, and key metabolic pathways of Bacillus sp. YM1 isolated from oily food waste compost

Xia Zhang; Muhammad Khalid; Saiqa Menhas; Yaowei Chi; Xijia Yang; Shaohua Chu; Pei Zhou; Dan Zhang

doi:10.1016/j.chemosphere.2023.140092

Insights into effects of salt stress on the oil-degradation capacity, cell response, and key metabolic pathways of Bacillus sp. YM1 isolated from oily food waste compost

Chemosphere. 2023 Nov:341:140092. doi: 10.1016/j.chemosphere.2023.140092. Epub 2023 Sep 6.

Authors

Xia Zhang¹, Muhammad Khalid², Saiqa Menhas¹, Yaowei Chi¹, Xijia Yang³, Shaohua Chu³, Pei Zhou⁴, Dan Zhang⁵

Affiliations

¹ School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, 200240, China; Key Laboratory of Urban Agriculture, Ministry of Agriculture and Rural Affairs, Shanghai, 200240, China.
² Department of Biology, College of Science and Technology, Wenzhou-Kean University, Wenzhou, 325000, China.
³ School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, 200240, China; Key Laboratory of Urban Agriculture, Ministry of Agriculture and Rural Affairs, Shanghai, 200240, China; Shanghai Yangtze River Delta Eco-Environmental Change and Management Observation and Research Station, Ministry of Science and Technology, Ministry of Education, Shanghai, 200240, China; Bor S. Luh Food Safety Research Center, Shanghai Jiao Tong University, Shanghai, 200240, China.
⁴ School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, 200240, China; Key Laboratory of Urban Agriculture, Ministry of Agriculture and Rural Affairs, Shanghai, 200240, China; Shanghai Yangtze River Delta Eco-Environmental Change and Management Observation and Research Station, Ministry of Science and Technology, Ministry of Education, Shanghai, 200240, China; Bor S. Luh Food Safety Research Center, Shanghai Jiao Tong University, Shanghai, 200240, China. Electronic address: peizhousjtu@163.com.
⁵ School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, 200240, China; Key Laboratory of Urban Agriculture, Ministry of Agriculture and Rural Affairs, Shanghai, 200240, China; Shanghai Yangtze River Delta Eco-Environmental Change and Management Observation and Research Station, Ministry of Science and Technology, Ministry of Education, Shanghai, 200240, China; Bor S. Luh Food Safety Research Center, Shanghai Jiao Tong University, Shanghai, 200240, China. Electronic address: zhdsjtu@sjtu.edu.cn.

PMID: 37678592
DOI: 10.1016/j.chemosphere.2023.140092

Abstract

A novel bacterial strain, Bacillus sp. YM1, was isolated from compost for the efficient degradation of oily food waste under salt stress. The strain's lipase activity, oil degradation ability, and tolerance to salt stress were evaluated in a liquid medium. Additionally, the molecular mechanisms (including key genes and functional processes) underlying the strain's salt-resistant degradation of oil were investigated based on RNA-Seq technology. The results showed that after 24 h of microbial degradation, the degradation rate of triglycerides in soybean oil was 80.23% by Bacillus sp. YM1 at a 30 g L^-1 NaCl concentration. The metabolizing mechanism of long-chain triglycerides (C50-C58) by the YM1 strain, especially the biodegradation rate of triglycerides (C18:3/C18:3/C18:3), could reach 98.65%. The most substantial activity of lipase was up to 325.77 U·L^-1 at a salinity of 30 g L^-1 NaCl. During salt-induced stress, triacylglycerol lipase was identified as the crucial enzyme involved in oil degradation in Bacillus sp. YM1, and its synthesis was regulated by the lip gene (M5E02_13495). Bacillus sp. YM1 underwent adaptation to salt stress through various mechanisms, including the accumulation of free amino acids, betaine synthesis, regulation of intracellular Na⁺/K⁺ balance, the antioxidative response, spore formation, and germination. The key genes involved in Bacillus sp. YM1's adaptation to salt stress were responsible for the synthesis of glutamate 5-kinase, superoxide dismutase, catalase, Na⁺/H⁺ antiporter, general stress protein, and sporogenic proteins belonging to the YjcZ family. Results indicated that the isolated strain of Bacillus sp. YM1 could significantly degrade oil in a short time under salt stress. This study would introduce new salt-tolerant strains for coping with the biodegradation of oily food waste and provide gene targets for use in genetic engineering.

Keywords: Bacillus sp. YM1; Biodegradation; High NaCl concentration; Oily food waste; Salt stress.

MeSH terms

Bacillus* / genetics
Composting*
Food
Metabolic Networks and Pathways
Refuse Disposal*
Sodium Chloride / pharmacology

Substances

Sodium Chloride