TY - JOUR
T1 - Production of cellulases and xylanases under catabolic repression conditions from mutant PR-22 of Cellulomonas flavigena
AU - Rojas-Rejón, Oscar A.
AU - Poggi-Varaldo, Héctor M.
AU - Ramos-Valdivia, Ana C.
AU - Martínez-Jiménez, Alfredo
AU - Cristiani-Urbina, Eliseo
AU - De La Torre Martínez, Mayra
AU - Ponce-Noyola, Teresa
N1 - Funding Information:
This work was supported by Consejo Nacional de Ciencia y Tecnología México (CONACYT) (Grant 104333).
PY - 2011/1
Y1 - 2011/1
N2 - Derepressed mutant PR-22 was obtained by N-methyl-N′-nitro-N- nitrosoguanidine (MNNG) mutagenic treatment of Cellulomonas flavigena PN-120. This mutant improved its xylanolytic activity from 26.9 to 40 U mg-1 and cellulolytic activity from 1.9 to 4 U mg-1; this represented rates almost 2 and 1.5 times higher, respectively, compared to its parent strain growing in sugarcane bagasse. Either glucose or cellobiose was added to cultures of C. flavigena PN-120 and mutant PR-22 induced with sugarcane bagasse in batch culture. The inhibitory effect of glucose on xylanase activity was more noticeable for parent strain PN-120 than for mutant PR-22. When 20 mM glucose was added, the xylanolytic activity decreased 41% compared to the culture grown without glucose in mutant PR-22, whereas in the PN-120 strain the xylanolytic activity decreased by 49% at the same conditions compared to its own control. Addition of 10 and 15 mM of glucose did not adversely affect CMCase activity in PR-22, but glucose at 20 mM inhibited the enzymatic activity by 28%. The CMCase activity of the PN-120 strain was more sensitive to glucose than PR-22, with a reduction of CMCase activity in the range of 20-32%. Cellobiose had a more significant effect on xylanase and CMCase activities than glucose did in the mutant PR-22 and parent strain. Nevertheless, the activities under both conditions were always higher in the mutant PR-22 than in the PN-120 strain. Enzymatic saccharification experiments showed that it is possible to accumulate up to 10 g l-1 of total soluble sugars from pretreated sugarcane bagasse with the concentrated enzymatic crude extract from mutant PR-22.
AB - Derepressed mutant PR-22 was obtained by N-methyl-N′-nitro-N- nitrosoguanidine (MNNG) mutagenic treatment of Cellulomonas flavigena PN-120. This mutant improved its xylanolytic activity from 26.9 to 40 U mg-1 and cellulolytic activity from 1.9 to 4 U mg-1; this represented rates almost 2 and 1.5 times higher, respectively, compared to its parent strain growing in sugarcane bagasse. Either glucose or cellobiose was added to cultures of C. flavigena PN-120 and mutant PR-22 induced with sugarcane bagasse in batch culture. The inhibitory effect of glucose on xylanase activity was more noticeable for parent strain PN-120 than for mutant PR-22. When 20 mM glucose was added, the xylanolytic activity decreased 41% compared to the culture grown without glucose in mutant PR-22, whereas in the PN-120 strain the xylanolytic activity decreased by 49% at the same conditions compared to its own control. Addition of 10 and 15 mM of glucose did not adversely affect CMCase activity in PR-22, but glucose at 20 mM inhibited the enzymatic activity by 28%. The CMCase activity of the PN-120 strain was more sensitive to glucose than PR-22, with a reduction of CMCase activity in the range of 20-32%. Cellobiose had a more significant effect on xylanase and CMCase activities than glucose did in the mutant PR-22 and parent strain. Nevertheless, the activities under both conditions were always higher in the mutant PR-22 than in the PN-120 strain. Enzymatic saccharification experiments showed that it is possible to accumulate up to 10 g l-1 of total soluble sugars from pretreated sugarcane bagasse with the concentrated enzymatic crude extract from mutant PR-22.
KW - Cellulase
KW - Cellulomonas flavigena
KW - Derepressed
KW - Mutant
KW - Saccharification
KW - Sugarcane bagasse
KW - Xylanase
UR - http://www.scopus.com/inward/record.url?scp=78651098930&partnerID=8YFLogxK
U2 - 10.1007/s10295-010-0821-7
DO - 10.1007/s10295-010-0821-7
M3 - Artículo
C2 - 20803244
AN - SCOPUS:78651098930
SN - 1367-5435
VL - 38
SP - 257
EP - 264
JO - Journal of Industrial Microbiology and Biotechnology
JF - Journal of Industrial Microbiology and Biotechnology
IS - 1
ER -