scholarly journals Mixed Acid Fermentation of Carbohydrate-Rich Dairy Manure Hydrolysate

2021 ◽  
Vol 9 ◽  
Author(s):  
Abel T. Ingle ◽  
Nathaniel W. Fortney ◽  
Kevin A. Walters ◽  
Timothy J. Donohue ◽  
Daniel R. Noguera
Keyword(s):  
Dairy Manure ◽  
Dilute Acid Pretreatment ◽  
Dilute Acid ◽  
Acid Pretreatment ◽  
Acid Fermentation ◽  
Mixed Culture Fermentation ◽  
Fermentation Products ◽  
Agricultural Residue ◽  
Mixed Acid ◽  
C4 Production

Dairy manure (DM) is an abundant agricultural residue that is largely composed of lignocellulosic biomass. The aim of this study was to investigate if carbon derived from DM fibers can be recovered as medium-chain fatty acids (MCFAs), which are mixed culture fermentation products of economic interest. DM fibers were subjected to combinations of physical, enzymatic, chemical, and thermochemical pretreatments to evaluate the possibility of producing carbohydrate-rich hydrolysates suitable for microbial fermentation by mixed cultures. Among the pretreatments tested, decrystalization dilute acid pretreatment (DCDA) produced the highest concentrations of glucose and xylose, and was selected for further experiments. Bioreactors fed DCDA hydrolysate were operated. Acetic acid and butyric acid comprised the majority of end products during operation of the bioreactors. MCFAs were transiently produced at a maximum concentration of 0.17 mg CODMCFAs/mg CODTotal. Analyses of the microbial communities in the bioreactors suggest that lactic acid bacteria, Megasphaera, and Caproiciproducens were involved in MCFA and C4 production during DCDA hydrolysate metabolism.

scholarly journals Genetic Engineering of Enterobacter asburiae Strain JDR-1 for Efficient Production of Ethanol from Hemicellulose Hydrolysates

2009 ◽  
Vol 75 (18) ◽  
pp. 5743-5749 ◽  
Author(s):  
Changhao Bi ◽  
Xueli Zhang ◽  
Lonnie O. Ingram ◽  
James F. Preston
Keyword(s):  
Ethanol Yield ◽  
Maximum Yield ◽  
Pyruvate Decarboxylase ◽  
Dry Weight ◽  
Dilute Acid Pretreatment ◽  
Efficient Production ◽  
Dilute Acid ◽  
Acid Pretreatment ◽  
Acid Fermentation ◽  
Enterobacter Asburiae

ABSTRACT Dilute acid pretreatment is an established method for hydrolyzing the methylglucuronoxylans of hemicellulose to release fermentable xylose. In addition to xylose, this process releases the aldouronate methylglucuronoxylose, which cannot be metabolized by current ethanologenic biocatalysts. Enterobacter asburiae JDR-1, isolated from colonized wood, was found to efficiently ferment both methylglucuronoxylose and xylose in acid hydrolysates of sweet gum xylan, producing predominantly ethanol and acetate. Transformation of E. asburiae JDR-1 with pLOI555 or pLOI297, each containing the PET operon containing pyruvate decarboxylase (pdc) and alcohol dehydrogenase B (adhB) genes derived from Zymomonas mobilis, replaced mixed-acid fermentation with homoethanol fermentation. Deletion of the pyruvate formate lyase (pflB) gene further increased the ethanol yield, resulting in a stable E. asburiae E1(pLOI555) strain that efficiently utilized both xylose and methylglucuronoxylose in dilute acid hydrolysates of sweet gum xylan. Ethanol was produced from xylan hydrolysate by E. asburiae E1(pLOI555) with a yield that was 99% of the theoretical maximum yield and at a rate of 0.11 g ethanol/g (dry weight) cells/h, which was 1.57 times the yield and 1.48 times the rate obtained with the ethanologenic strain Escherichia coli KO11. This engineered derivative of E. asburiae JDR-1 that is able to ferment the predominant hexoses and pentoses derived from both hemicellulose and cellulose fractions is a promising subject for development as an ethanologenic biocatalyst for production of fuels and chemicals from agricultural residues and energy crops.

scholarly journals Olive tree pruning as an agricultural residue for ethanol production. Fermentation of hydrolysates from dilute acid pretreatment

2012 ◽  
Vol 10 (3) ◽  
pp. 643 ◽  
Author(s):  
M. J. Díaz-Villanueva ◽  
C. Cara-Corpas ◽  
E. Ruiz-Ramos ◽  
I. Romero-Pulido ◽  
E. Castro-Galiano
Keyword(s):  
Ethanol Production ◽  
Olive Tree ◽  
Dilute Acid Pretreatment ◽  
Dilute Acid ◽  
Acid Pretreatment ◽  
Agricultural Residue ◽  
Tree Pruning

scholarly journals Chemical Methods for Hydrolyzing Dairy Manure Fiber: A Concise Review

Energies ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 6159
Author(s):  
Noori M. Cata Saady ◽  
Fatemeh Rezaeitavabe ◽  
Juan Enrique Ruiz Espinoza
Keyword(s):  
Anaerobic Digestion ◽  
Ultrasound Irradiation ◽  
Dairy Manure ◽  
Dilute Acid Pretreatment ◽  
Hydrolysis Rate ◽  
Cellulolytic Enzymes ◽  
Chemical Agent ◽  
Dilute Acid ◽  
Acid Pretreatment ◽  
Monolithic Components

This paper reviews the chemical hydrolysis processes of dairy manure fiber to make its sugar accessible to microorganisms during anaerobic digestion and identifies obstacles and opportunities. Researchers, so far, investigated acid, alkali, sulfite, and advanced oxidation processes (such as hydrogen peroxide assisted by microwave/ultrasound irradiation, conventional boiling, and wet oxidation), or their combinations. Generally, dilute acid (3–10%) is less effective than concentrated acid (12.5–75%), which decrystallizes the cellulose. Excessive alkaline may produce difficult-to-degrade oxycellulose. Therefore, multi-step acid hydrolysis (without alkaline) is preferred. Such processes yielded 84% and 80% manure-to-glucose and -xylose conversion, respectively. Acid pretreatment increases lignin concentration in the treated manure and hinders subsequent enzymatic processes but is compatible with fungal cellulolytic enzymes which favor low pH. Manure high alkalinity affects dilute acid pretreatment and lowers glucose yield. Accordingly, the ratio of manure to the chemical agent and its initial concentration, reaction temperature and duration, and manure fineness need optimization because they affect the hydrolysis rate. Optimizing these factors or combining processes should balance removing hemicellulose and/or lignin and increasing cellulose concentrations while not hindering any subsequent process. The reviewed methods are neither economical nor integratable with the on-farm anaerobic digestion. Economic analysis and energy balance should be monolithic components of the research. More research is required to assess the effects of nitrogen content on these processes, optimize it, and determine if another pretreatment is necessary.

scholarly journals Understanding the effects of different residual lignin fractions in acid-pretreated bamboo residues on its enzymatic digestibility

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Wenqian Lin ◽  
Jinlai Yang ◽  
Yayue Zheng ◽  
Caoxing Huang ◽  
Qiang Yong
Keyword(s):  
Enzymatic Hydrolysis ◽  
Negative Impact ◽  
Dilute Acid Pretreatment ◽  
Residual Lignin ◽  
Dilute Acid ◽  
Enzymatic Digestibility ◽  
Acid Pretreatment ◽  
Organic Reagents ◽  
Milled Wood Lignin ◽  
Affinity Constants

Abstract Background During the dilute acid pretreatment process, the resulting pseudo-lignin and lignin droplets deposited on the surface of lignocellulose and inhibit the enzymatic digestibility of cellulose in lignocellulose. However, how these lignins interact with cellulase enzymes and then affect enzymatic hydrolysis is still unknown. In this work, different fractions of surface lignin (SL) obtained from dilute acid-pretreated bamboo residues (DAP-BR) were extracted by various organic reagents and the residual lignin in extracted DAP-BR was obtained by the milled wood lignin (MWL) method. All of the lignin fractions obtained from DAP-BR were used to investigate the mechanism for interaction between lignin and cellulase using surface plasmon resonance (SPR) technology to understand how they affect enzymatic hydrolysis Results The results showed that removing surface lignin significantly decreased the yield for enzymatic hydrolysis DAP-BR from 36.5% to 18.6%. The addition of MWL samples to Avicel inhibited its enzymatic hydrolysis, while different SL samples showed slight increases in enzymatic digestibility. Due to the higher molecular weight and hydrophobicity of MWL samples versus SL samples, a stronger affinity for MWL (KD = 6.8–24.7 nM) was found versus that of SL (KD = 39.4–52.6 nM) by SPR analysis. The affinity constants of all tested lignins exhibited good correlations (r > 0.6) with the effects on enzymatic digestibility of extracted DAP-BR and Avicel. Conclusions This work revealed that the surface lignin on DAP-BR is necessary for maintaining enzyme digestibility levels, and its removal has a negative impact on substrate digestibility.

scholarly journals A Process Study of Lactic Acid Production from Phragmites australis Straw by a Thermophilic Bacillus coagulans Strain under Non-Sterilized Conditions

Processes ◽  
2018 ◽  
Vol 6 (10) ◽  
pp. 175 ◽  
Author(s):  
Yuming Zhang ◽  
Mengran Li ◽  
Tian Nie ◽  
Zhihua Ni
Keyword(s):  
Lactic Acid ◽  
Phragmites Australis ◽  
Lactic Acid Production ◽  
Scale Up ◽  
Bacillus Coagulans ◽  
Dilute Acid Pretreatment ◽  
Integrated Process ◽  
Dilute Acid ◽  
Acid Pretreatment ◽  
Process Study

Phragmites australis straw (PAS) is an abundant and renewable wetland lignocellulose. Bacillus coagulans IPE22 is a robust thermophilic strain with pentose-utilizing capability and excellent resistance to growth inhibitors. This work is focused on the process study of lactic acid (LA) production from P. australis lignocellulose which has not been attempted previously. By virtue of thermophilic feature of strain IPE22, two fermentation processes (i.e., separated process and integrated process), were developed and compared under non-sterilized conditions. The integrated process combined dilute-acid pretreatment, hemicellulosic hydrolysates fermentation, and cellulose utilization. Sugars derived from hemicellulosic hydrolysates and cellulose enzymatic hydrolysis were efficiently fermented to LA in a single vessel. Using the integrated process, 41.06 g LA was produced from 100 g dry PAS. The established integrated process results in great savings in terms of time and labor, and the fermentation process under non-sterilized conditions is easy to scale up for economical production of lactic acid from PAS.

Sign in / Sign up

Export Citation Format

Share Document