Enzymatic hydrolysate from non-pretreated biomass of yellow poplar (Liriodendron tulipifera) is an alternative resource for bioethanol production
Yellow poplar (Liriodendron tulipifera) has been the main alternative regarding the utilization of short-rotation forest for the production of bioenergy like heat and power. Enzymatic hydrolysate from non pre-treated biomass of yellow poplar was prepared and used as resource for bioethanol production. Fresh branch (1 year old) of yellow poplar biomass was found to be a good resource for achieving high saccharification yields and bioethanol production. Chemical composition of yellow poplar varied significantly depending upon age of tree. Cellulose content in fresh branch and log (12 years old) of yellow poplar was 44.7 and 46.7% respectively. Enzymatic hydrolysis of raw biomass was carried out with commercial enzymes. Fresh branch of yellow poplar hydrolyzed more easily than log of yellow poplar tree. After 72 h of enzyme treatment the glucose concentration from Fresh branch of yellow poplar was 1.46 g/L and for the same treatment period log of poplar produced 1.23 g/L of glucose. Saccharomyces cerevisiae KCTC 7296 fermented the enzyme hydrolysate to ethanol, however ethanol production was similar (~1.4 g/L) from both fresh branch and log yellow poplar hydrolysates after 96 h. The study indicated that fresh branch tree of yellow poplar was found to be a good biomass resource to achieve a high saccharification yield and bioethanol production without pretreatment process.