TY - JOUR
T1 - Transient responses of Wickerhamia sp. yeast continuous cultures to qualitative changes in carbon source supply
T2 - induction and catabolite repression of α-amylase synthesis
AU - Chávez-Camarillo, Griselda Ma
AU - Santiago-Flores, Uriel Mauricio
AU - Mena-Vivanco, Armando
AU - Morales-Barrera, Liliana
AU - Cortés-Acosta, Elias
AU - Cristiani-Urbina, Eliseo
N1 - Publisher Copyright:
© 2018, Springer-Verlag GmbH Germany, part of Springer Nature and the University of Milan.
PY - 2018/10/1
Y1 - 2018/10/1
N2 - The purpose of this study was to evaluate the inductive effect of starch and maltose, and the repressive/inhibitory effect of glucose, on amy-1 gene expression and α-amylase production by Wickerhamia sp., using continuous culture under transient-state conditions at a dilution rate (D) of 0.083 h−1. Induction and repression kinetics of α-amylase were studied by changing the medium feed from glucose to maltose or starch in the induction experiments and vice versa in the repression experiments. Expression levels of amy-1 gene were measured by RT-qPCR. Results showed that starch was a more efficient inducer of α-amylase synthesis compared to maltose, with maximum accumulation rate constants of 0.424 and 0.191 h−1, respectively. In contrast, α-amylase synthesis in starch and maltose cultures was partially repressed by glucose as indicated by a specific activity close to basal levels and a decay constant rate (− 0.065 and − 0.069 h−1, respectively) higher than − D. A linear dependence of the specific rate of α-amylase production on mRNA relative abundance of amy-1 gene was observed. An inhibitory effect of glucose was not observed even at a concentration of 30 g L−1. In conclusion, the transient continuous culture is a useful tool to determine the qualitative and quantitative effects of maltose and starch on α-amylase induction and of glucose on enzyme repression, as well as to obtain a detailed understanding of the dynamic behavior of the yeast culture. Furthermore, results showed that amylaceous substrates can be very effective carbon sources for the production of α-amylase without being inhibited by glucose.
AB - The purpose of this study was to evaluate the inductive effect of starch and maltose, and the repressive/inhibitory effect of glucose, on amy-1 gene expression and α-amylase production by Wickerhamia sp., using continuous culture under transient-state conditions at a dilution rate (D) of 0.083 h−1. Induction and repression kinetics of α-amylase were studied by changing the medium feed from glucose to maltose or starch in the induction experiments and vice versa in the repression experiments. Expression levels of amy-1 gene were measured by RT-qPCR. Results showed that starch was a more efficient inducer of α-amylase synthesis compared to maltose, with maximum accumulation rate constants of 0.424 and 0.191 h−1, respectively. In contrast, α-amylase synthesis in starch and maltose cultures was partially repressed by glucose as indicated by a specific activity close to basal levels and a decay constant rate (− 0.065 and − 0.069 h−1, respectively) higher than − D. A linear dependence of the specific rate of α-amylase production on mRNA relative abundance of amy-1 gene was observed. An inhibitory effect of glucose was not observed even at a concentration of 30 g L−1. In conclusion, the transient continuous culture is a useful tool to determine the qualitative and quantitative effects of maltose and starch on α-amylase induction and of glucose on enzyme repression, as well as to obtain a detailed understanding of the dynamic behavior of the yeast culture. Furthermore, results showed that amylaceous substrates can be very effective carbon sources for the production of α-amylase without being inhibited by glucose.
KW - Catabolite repression
KW - Induction
KW - Transient continuous culture
KW - Wickerhamia sp
KW - amy-1 gene
KW - α-Amylase
UR - http://www.scopus.com/inward/record.url?scp=85052817873&partnerID=8YFLogxK
U2 - 10.1007/s13213-018-1369-4
DO - 10.1007/s13213-018-1369-4
M3 - Artículo
SN - 1590-4261
VL - 68
SP - 625
EP - 635
JO - Annals of Microbiology
JF - Annals of Microbiology
IS - 10
ER -