Highest Bioethanol Concentration Research Articles

Hybrid pathway of bio-ethanol production employing empty fruit bunches co-gasified with charcoal and mixed culture fermentation: Optimization using response surface methodology

The research focuses on the synthesis of syngas from lignocellulosic biomass via co-gasification, employing response surface methodology. In addition, the study aims to optimize syngas fermentation efficiency for bioethanol production, utilizing two species of microorganisms – Saccharomyces cerevisiae and Clostridium butyricum – within an integrated biorefinery framework. The raw syngas was generated through the co-gasification of empty fruit bunches and charcoal mixtures (75:25). The optimal ratio of these components was determined via central composite design. The individual performances of S. cerevisiae and C. butyricum, as well as their co-fermentation, were thoroughly investigated, considering parameters such as colony forming units (CFU), pH, total organic carbon (TOC), and syngas flow rate. Morphological features of microorganisms during syngas fermentation were characterized using field emission scanning electron microscopy analysis. The results indicated that the highest bioethanol concentration, reaching 31.20 mmol, was achieved through co-fermentation as opposed to single-inoculum fermentation. Furthermore, a significant increase (3.08%) in bioethanol productivity was observed when the syngas flow rate was elevated from 50 to 1000 mL/min. Therefore, microbial co-fermentation emerges as a promising strategy to enhance bioethanol production from syngas derived from lignocellulosic biomass. Highlights Parametric optimization for co-gasification using response surface methodology Syngas was co-fermented using Saccharomyces cerevisiae and Clostridium butyricum Effects of syngas (CFU, pH, and TOC) were investigated during co-fermentation Bioethanol production increased 3.08% when syngas flowrate increased from (50 to 1000 mL/min)

Potential of cellulose from wood waste for immobilization Saccharomyces cerevisiae in bioethanol production

Bioethanol is a sustainable alternative fuel that needs further research. In this work, bioethanol production was carried out through the fermentation of an immobilized yeast cells in alginate/cellulose beads for five cycles. Cellulose was successfully isolated from wood waste and used as a filler to reinforce alginate beads. The effects of alginate/cellulose (AC) ratios (1:0, 1:1, 2:3, and 3:2) on bioethanol yield, concentration, microbial leaching, and surface matrix morphology have been investigated. Infrared analysis results revealed no lignin or lignocellulose in the isolated wood waste cellulose structure, confirming that the extracted cellulose shares the same characteristics as commercial microcrystalline cellulose (MCC). The fermentation rate of alginate/cellulose beads was three times greater than that of neat alginate. The highest bioethanol concentration (increasing up to 114,5 g/L) resulted from AC 3:2 beads for five cycles. The beads can be reused effectively in fermentation for up to four cycles. The results of the microbial leaching test demonstrate that up to 95 % more yeast is effectively kept inside the matrix when a small amount of cellulose is present in the beads in all ratios. These findings indicate that the yeast is strongly interacting with the cellulose matrix, as confirmed via the scanning electron microscopy analysis.

Enhancement of Fermentable Sugars Obtained from<i> Amorphophallus</i> Spp. Tuber for Bioethanol Production by Optimizing Temperature and Pretreatment Concentration

Biofuels have been regaining popularity due to the increasing price of non-renewable fuels and the higher carbon dioxide emissions. Biofuels are manufactured from plant products and are mainly composed of lignocellulose and starch materials. This investigation aims to produce increased fermentable sugars for enhanced bioethanol production from tubers procured from northern Thailand. Varying concentrations of H2SO4 is used to pretreat the tubers. Before hydrolyzing with cellulase enzymes, the tubers were chopped into small pieces (1-2 cm), dried in a solar oven, powdered. The obtained results confirmed that the fermentable/ reducing sugar content of Amorphophallus spp. (suweg) tuber increased from 2.6 g/L to 19.01 g/L after enzymatic hydrolysis. The enzymes act as an excellent way to speed up the hydrolysis process. The theoretical potential of bioethanol production was calculated under ideal conditions, with the highest bioethanol concentration obtained is 9.69 ± 0.12 g/L at 0.4 % H2SO4 (pretreatment conc.) and 75 °C. The enhanced fermentable sugars obtained from starchy tubers may be utilized for bioethanol production to overcome depleting fossil fuels.

Production of high concentration bioethanol from reed by combined liquid hot water and sodium carbonate-oxygen pretreatment

This study aimed to establish a method of producing high-concentration bioethanol from reed with reduced distillation-energy demand. Reed was subjected to a pretreatment combining liquid hot water (LHW) and sodium carbonate with oxygen (LHW–Na2CO3/O2) to increase substrate concentration and further achieve high bioethanol concentration through fed-batch semi-simultaneous saccharification and fermentation (fed-batch S-SSF). An oxygen pressure of 0.8 MPa, a Na2CO3 dosage of 16%, a reaction temperature of 160 °C, and a reaction time of 60 min were determined to be optimal, resulting in the highest bioethanol concentration (66.5 g L−1). Bioethanol concentration increased by 75.9% and resulted in a 76.6% decrease in distillation energy compared with those obtained by single-stage LHW pretreatment at 170 °C. After the LHW–Na2CO3/O2 pretreatment, the rate of lignin removal was 71.4%, and almost all hemicellulose was removed. Lignin and hemicellulose removal weakened the interactions among cellulose, hemicellulose, and lignin. We focused on the maximum utilization of biomass resources and decrease in energy expenditure, which highlighted the potential use of the combined LHW–Na2CO3/O2 pretreatment with fed-batch S-SSF method in the industrialization of bioethanol production from reed.

Valorisation of cassava peels through simultaneous saccharification and ethanol production: Effect of prehydrolysis time, kinetic assessment and preliminary scale up

This study optimised bioethanol production from cassava peel waste using simultaneous saccharification and fermentation (SSF) processes with prehydrolysis time (PTSSF) as an input parameter and without prehydrolysis time (WPTSSF). The highest bioethanol concentration was observed with the optimized WPTSSF process (16.42 ± 0.26 g/L). Moreover, the kinetics of yeast growth and ethanol production showed a maximum specific growth rate (µmax) of 1.851 h−1 for the PTSSF process while the WPTSSF had the highest maximum potential bioethanol concentration (Pm) (16.80 g/L). Preliminary assessment in 0.5 L and 5 L scale up processes gave a 2-fold increase in the Pm values for the WPTSSF processes compared to the flask system. Major knowledge gaps on navigating the optimization search space for prehydrolysis inclusion with other key parameters in SSF processes was elucidated. Additionally, kinetic modelling and preliminary scale up generated valuable insights for SSF bioethanol process design using starch-based wastes.

Effect of Time Fermentation and Saccharomyces Cerevisiae Concentration for Bioethanol Production from Empty Fruit Bunch

Bioethanol is new renewable energy using the fermentation process from a substrate containing glucose. One of the materials which can convert to bioethanol is empty fruit bunch, which is in large amount in Indonesia. The plantation of palm oil has empty fruit bunch waste as much 23.988.293 tons in a year. The conversion from an empty fruit bunch to bioethanol also helps to reuse the waste which is not useful. There are a few steps to get bioethanol from an empty fruit bunch that is delignification of empty fruit bunch pollen using KOH solution which makes from empty fruit bunch ash getting from an incinerator. And then purification of pollen using H2O2 3% solution, hydrolysis cellulose becomes glucose solution using H2SO4 1% in process condition 100 °C and 60 minutes. Fermentation using temperature condition 30 °C, and stirring in 250 rpm. The variation of yeast Saccharomyces cerevisiae concentration which is 4 g/L, 6 g/L, and 8 g/L. And time variation in 0, 24, 48, 72, 96, and 120 hours. The research result is shown that maximum glucose from hydrolysis is 112,44 g/L. And the highest bioethanol concentration from the process is 5,5% (v/v) or 41,411 g/L in yeast concentration 6 g/L and 96 hours.

Usage of thermophilic cyanobacterial biomass for bioethanol production

Although the usage of microalgae biomass as a feedstock for bioethanol production has been extensively studied, very little attention has been given to the usage of cyanobacterial biomass for bioethanol production. In this study, a thermophilic cyanobacterial strain namely Phormidium sp. was used for producing bioethanol. Some important parameters for bioethanol production were optimized. When the initial sugar concentration was 8.69 at 40 g L−1 cyanobacteria loading, Pichia stipitis used 31.5% of the sugar and produced 1.64 g L−1 ethanol and Saccharomyces cerevisiae used 34.6% of the sugar and produced 1.97 g L−1 ethanol at the end of 72 h. The highest bioethanol concentration was obtained as 2.32 g L−1 for S. cerevisiae and 1.7 g L−1 for P. stipitis at 24 h of incubation time and substrate concentration of 40 g L−1 cyanobacterial biomass at pH 5. This study demonstrated that the biomass of a thermophilic cyanobacteria is a promising feedstock for bioethanol production. © 2014 American Institute of Chemical Engineers Environ Prog, 34: 903–907, 2015