BioChem - DOS

Study of influence of yeast cells treatment on sugarcane ethanol fermentation: Operating conditions and kinetics

Biochemical engineering journal

Yamakawa, Celina K.; Ccopa Rivera, Elmer; Kwon, Hyun; Herrera Agudelo, William E.; Saad, Marcelo B.W.; Leal, Jairo; Rossell, Carlos E.V.; Bonomi, Antonio; Maciel Filho, Rubens

<P><B>Abstract</B></P> <P>In this work, the effects of various operating parameters of the two-stage yeast treatment on the VHG fermentation performance were evaluated. First, a central composite design was used to investigate the effects of temperature and pH on cell viability and flocculation dispersion in the acid treatment unit (1<SUP>st</SUP> stage). Second, the effects of temperature, oxidation-reduction potential (ORP) and sugar concentration in the yeast reactivation (2<SUP>nd</SUP> stage) on the performance parameters (productivity, ethanol yield and cell viability) of the VHG fermentation were evaluated through a full factorial design. The results indicated that the acid treatment around 2.65 pH and temperature controlled at 30 &deg;C for 30 min led to higher cell viability. The conditions of yeast reactivation stage that positively influenced the VHG fermentation performance were relatively low temperature and negative ORP. A mechanistic model quantitatively revealed the influence of the operating parameters studied on cell growth kinetics. The two-stage yeast treatment promoted the increase in cell viability through the cell membrane recovery, which led to the maintenance or improvement the VHG fermentation performance.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A two-stage yeast treatment is critical to maintain VHG fermentation with cell recycling. </LI> <LI> The optimal conditions of acid treatment stage were 30 &deg;C, 2.65 pH and 30 min. </LI> <LI> The highest cell viability was found at relatively low temperature and negative ORP. </LI> <LI> Reaction rates were calculated for the yeast reactivation stage using a mechanistic model. </LI> <LI> Real-time measurements yielded valuable information to modeling and optimization. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

2019

Elsevier

1369-703x

147

pp.1-10

10.1016/j.bej.2019.03.022

http://click.ndsl.kr/servlet/OpenAPIDetailView?keyValue=05787966&target=NART&cn=NART106571487

https://backend.orbit.dtu.dk/ws/files/178145356/Yamakawa_et_al_2019_Study_of_influence_of_yeast_accepted.pdf

Yeast recycling; Kinetic modeling; Cell viability; Very-high-gravity fermentation; Ethanol