Hoda Nouri, Mehrdad Azin, Mir Latif Mousavi
Ann Microbiol (2017) 67:633–641 DOI 10.1007/s13213-017-1292-0
Abstract Sugarcane bagasse is one of the low-cost substrates
used for bioethanol production. In order to solubilize sugars in
hemicelluloses like xylan, a new thermotolerant isolate of
Candida tropicalis HNMA-1 with xylan-hydrolyzing ability
was identified and characterized. The strain showed relative
tolerance to high temperature. Our results demonstrated
0.211 IU ml
xylanase activity at 40 °C compared to
0.236 IU ml
at 30 °C. The effect of high temperature on
the growth and fermentation of xylose and sugarcane bagasse
hydrolysate were also investigated. In both xylose or hydrolysate
medium, increased growth was recorded at 40 °C.
Meanwhile, the efficiency of ethanol fermentation was adversely
affected by temperature since yields of 0.088 g g
in the xylose medium, in addition to
0.090 g g
in the hydrolysate medium were
noticed at 30 °C and 40 °C, respectively. Inhibitory compounds
in the hydrolysate medium demonstrated negative effects
on fermentation and productivity, with maximum ethanol
concentration attained after 48 h in the hydrolysate, as
opposed to 24 h in the xylose medium. Our data show that
the newly thermotolerant isolate, C. tropicalis HNMA-1, is
able to efficiently ferment xylose and hydrolysate, and also
has the capacity for application in ethanol production from
hemicellulosic sources.