Production of medium-chain volatile fatty acids by mixed ruminal microorganisms is enhanced by ethanol in co-culture with Clostridium kluyveri

Mixed Carboxylic Acid Production by Megasphaera elsdenii from Glucose and Lignocellulosic Hydrolysate

“…Choi et al [20] reached a combined BA and HA titer of 32.0 g/L from sucrose in liquid-liquid extractive fermentation also by M. elsdenii. Bacterial co-cultures and mono-culture fermentations of C. kluyveri using acetate and ethanol as carbon sources produced HA titers of < 10 and 12.8 g/L, respectively [13,15,18,19] and Clostridium sp. BS-1 has been reported to produce up to 32 g/L of HA in 16 days from galactitol.…”

Enhancing Biomass Utilization for Bioenergy — Crop Rotation Systems and Alternative Conversion Processes

“…It has been demonstrated that the addition of dilute amounts of ethanol to mixed culture fermentations in the carboxylate platform results in the extension of the short chain VFAs to medium length molecules thus capturing the fuel value of ethanol in a form that could be more easily recovered [34,39]. What is unique and promising about the work of Weimer et.al., is the ability to speed up this process using ruminal mixed culture fermentations as opposed to the typical source of sewage digesters [38]. In addition they found that supplementing the mixture with ruminal derived Clostridiumum kluyveri an ethanol-utilizing bacteria resulted in production levels of 4.9-6.1 g/L of caproate in 48-72 hours using either switchgrass or alfalfa stems as the substrate.…”

“…Being able to generate longer VFAs increases the energy density in each molecule increasing the value of the material for liquid fuels. In addition, the longer chain VFAs are easier to extract from the fermentation media decreasing recovery costs [38][39]. For any biomass to biofuel production process a key element is being able to produce sufficient amounts of fuel molecules in short periods of time and with limited inputs.…”

“…In most cases the CBP system does not produce sufficient ethanol to be cost effective [41]. However, coupled with a ruminal microbial based carboxylate platform the limited ethanol production could be effectively utilized to produce longer chain VFAs increasing energy density of each molecule [38]. Volatile fatty acids must be converted to a form that increases their volatility to be good energy molecules.…”

Processamento do glicerol bruto em reatores anaeróbios de leito fluidificado, acidogênico e metanogênico, em temperatura mesofílica

“…Entretanto, a concentração de HCa entre 800 e 900 mg.L -1 , em pH ácido (aproximadamente 5), é considerada uma concentração de inibição ao sistema (GE et al, 2015;WEIMER; NERDAHL; BRANDL, 2015). Verifica-se que para os TDH de 8, 6 e 4 h, no qual o pH do sistema foi aproximadamente 5 (conforme item 5.1.6), as concentrações de HCa foram, respectivamente 811,3; 1049,6 e 1097,7 mg.L -1 .…”