Screening a strain of Aspergillus niger and optimization of fermentation conditions for degradation of aflatoxin B₁.
Aflatoxin B₁, a type of highly toxic mycotoxin produced by some species belonging to the Aspergillus genus, such as Aspergillus flavus and Aspergillus parasiticus, is widely distributed in feed matrices. Here, coumarin was used as the sole carbon source to screen microorganism strains that were isolated from types of feed ingredients. Only one isolate (ND-1) was able to degrade aflatoxin B₁ after screening. ND-1 isolate, identified as a strain of Aspergillus niger using phylogenetic analysis on the basis of 18S rDNA, could remove 26.3% of aflatoxin B₁ after 48 h of fermentation in nutrient broth (NB). Optimization of fermentation conditions for aflatoxin B₁ degradation by selected Aspergillus niger was also performed. These results showed that 58.2% of aflatoxin B₁ was degraded after 24 h of culture under the optimal fermentation conditions. The aflatoxin B₁ degradation activity of Aspergillus niger supernatant was significantly stronger than cells and cell extracts. Furthermore, effects of temperature, heat treatment, pH, and metal ions on aflatoxin B₁ degradation by the supernatant were examined. Results indicated that aflatoxin B₁ degradation of Aspergillus niger is enzymatic and this process occurs in the extracellular environment.
Institute of Animal Nutrition, Northeast Agricultural University, Harbin 150030, China. dianjini2012@163.com.
Wei
W
Zhang
Institute of Animal Nutrition, Northeast Agricultural University, Harbin 150030, China. shanshimen@163.com.
Beibei
B
Xue
Institute of Animal Nutrition, Northeast Agricultural University, Harbin 150030, China. sjzlimengmeng@163.com.
Mengmeng
M
Li
Institute of Animal Nutrition, Northeast Agricultural University, Harbin 150030, China. muyangmyqq@163.com.
Yang
Y
Mu
Institute of Animal Nutrition, Northeast Agricultural University, Harbin 150030, China. chenzh1980@163.com.
Zhihui
Z
Chen
Institute of Animal Nutrition, Northeast Agricultural University, Harbin 150030, China. ljpneau@163.com.
Jianping
J
Li
Institute of Animal Nutrition, Northeast Agricultural University, Harbin 150030, China. asshan@neau.edu.cn.
Anshan
A
Shan
D016604:Aflatoxin B1 / Q000378:metabolism*; D001234:Aspergillus niger / Q000145:classification / Q000254:growth & development / Q000302:isolation & purification / Q000378:metabolism*; D002274:Carcinogens, Environmental / Q000378:metabolism*; D002474:Cell-Free System; D002681:China; D003374:Coumarins / Q000378:metabolism; D002523:Edible Grain / Q000382:microbiology; D005285:Fermentation; D005506:Food Contamination / Q000517:prevention & control*; D005656:Fungal Proteins / Q000378:metabolism*; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007700:Kinetics; D008670:Metals / Q000378:metabolism; D058889:Molecular Typing; D010802:Phylogeny; D013045:Species Specificity; D013213:Starch / Q000378:metabolism; D013379:Substrate Specificity
D002274:Carcinogens, Environmental; D003374:Coumarins; D005656:Fungal Proteins; D008670:Metals; D013213:Starch; D016604:Aflatoxin B1; C030123:coumarin