RESUMO
The production of succinic acid from corn stover is a promising and sustainable route; however, during the pretreatment stage, byproducts such as organic acids, furan-based compounds, and phenolic compounds generated from corn stover inhibit the microbial fermentation process. Selecting strains that are resistant to stress and utilizing nondetoxified corn stover hydrolysate as a feedstock for succinic acid production could be effective. In this study, A. succinogenes CICC11014 was selected as the original strain, and the stress-resistant strain A. succinogenes M4 was obtained by atmospheric and room temperature plasma (ARTP) mutagenesis and further screening. Compared to the original strain, A. succinogenes M4 exhibited a twofold increase in stress resistance and a 113% increase in succinic acid production when hydrolysate was used as the substrate. By conducting whole-genome resequencing of A. succinogenes M4 and comparing it with the original strain, four nonsynonymous gene mutations and two upstream regions with base losses were identified. KEY POINTS: ⢠A high-stress-resistant strain A. succinogenes M4 was obtained by ARTP mutation ⢠The production of succinic acid increased by 113% ⢠The mutated genes of A. succinogenes M4 were detected and analyzed.
Assuntos
Actinobacillus , Zea mays , Zea mays/química , Ácido Succínico , Melhoramento Vegetal , Fermentação , MutaçãoRESUMO
Utilizing CO2 for bio-succinic acid production is an attractive approach to achieve carbon capture and recycling (CCR) with simultaneous production of a useful platform chemical. Actinobacillus succinogenes and Basfia succiniciproducens were selected and investigated as microbial catalysts. Firstly, the type and concentration of inorganic carbon concentration and glucose concentration were evaluated. 6 g C/L MgCO3 and 24 g C/L glucose were found to be the optimal basic operational conditions, with succinic acid production and carbon yield of over 30 g/L and over 40%, respectively. Then, for maximum gaseous CO2 fixation, carbonate was replaced with CO2 at different ratios. The "less carbonate more CO2" condition of the inorganic carbon source was set as carbonate: CO2 = 1:9 (based on the mass of carbon). This condition presented the highest availability of CO2 by well-balanced chemical reaction equilibrium and phase equilibrium, showing the best performance with regarding CO2 fixation (about 15 mg C/(L·hr)), with suppressed lactic acid accumulation. According to key enzymes analysis, the ratio of phosphoenolpyruvate carboxykinase to lactic dehydrogenase was enhanced at high ratios of gaseous CO2, which could promote glucose conversion through the succinic acid path. To further increase gaseous CO2 fixation and succinic acid production and selectivity, stepwise CO2 addition was evaluated. 50%-65% increase in inorganic carbon utilization was obtained coupled with 20%-30% increase in succinic acid selectivity. This was due to the promotion of the succinic acid branch of the glucose metabolism, while suppressing the pyruvate branch, along with the inhibition on the conversion from glucose to lactic acid.
Assuntos
Dióxido de Carbono , Ácido Succínico , Dióxido de Carbono/metabolismo , Ácido Succínico/metabolismo , Actinobacillus/metabolismo , Glucose/metabolismoRESUMO
RATIONALE: Actinobacillus ureae (A. ureae) is an unusual commensal of human respiratory flora, rarely causing human infection. The predisposing factors, identification, clinical features, and antibiotic therapy of A. ureae are seldomly reported. Herein, we present a case of 64-year-old man affected by A. ureae pneumonia after intracranial surgery. PATIENT CONCERNS AND DIAGNOSES: A 64-year-old male was admitted with vomiting, drowsiness, and a severe disturbance of consciousness and was later diagnosed with cerebral hemorrhage by computed tomography images. After a craniocerebral surgery, the patient suffered from intractable pneumonia, experiencing treatment failure with multiple anti-bacterial agents. Sputum culture yield pure colonies of A. ureae, confirmed by matrix-assisted laser desorption/ionization time of flight and 16S rRNA gene sequencing. INTERVENTIONS: Minocycline (100 mg p.o. per 12 hours) with a course of 15 days was administrated for this patient. OUTCOMES: The respiratory symptoms, presenting as intermittent coughing with purulent and yellowish sputum, were gone. A 3-month follow-up examination showed a complete resolution of radiological findings. LESSONS: Clinically, the actual incidence of A. ureae pneumonia may be higher than that we generally recognized, and clinicians should consider A. ureae as a possible etiologic agent in patients with predispositions. Currently, A. ureae may be susceptible to penicillin, ampicillin, and third-generation cephalosporins. Other antibacterial agents, such as tetracycline, amoxicillin/clavulanic acid, and aminoglycosides also respond well and can be a choice in the treatment of A. ureae infections.
Assuntos
Infecções por Actinobacillus , Actinobacillus , Pneumonia , Masculino , Humanos , Pessoa de Meia-Idade , RNA Ribossômico 16S , Infecções por Actinobacillus/diagnóstico , Infecções por Actinobacillus/tratamento farmacológico , Infecções por Actinobacillus/microbiologia , Antibacterianos/uso terapêutico , Pneumonia/complicaçõesRESUMO
OBJECTIVES: The aim of this study was to characterize the floR-carrying plasmids originating from Glaesserella parasuis and Actinobacillus indolicus isolated from pigs with respiratory disease in China. METHODS: A total of 125 G. parasuis and 28 A. indolicus strains collected between 2009 and 2022 were screened for florfenicol resistance. Characterization of floR-positive isolates and plasmids were determined by antimicrobial susceptibility testing, serotyping, multilocus sequence typing (MLST), conjugation and transformation assays, whole-genome sequencing (WGS), and phylogenetic analysis. RESULTS: One A. indolicus and six G. parasuis were identified as positive for floR. The six G. parasuis were assigned to four different serovars, including serovars 6, 7, 9, and unknown. In addition to strain XP11, six floR genes were located on plasmids. The six floR-bearing plasmids could be transformed into Pasteurella multocida and divided into two different types, including â¼5000 bp and â¼6000 bp plasmids. The â¼5000 bp plasmids consisting of rep, lysR, mobB, and floR genes, exhibited high similarity among Pasteurellaceae bacteria. Furthermore, the â¼6000 bp plasmids, consisting of rep, lysR, mobC, mobA/L, and floR genes, showed high similarity between G. parasuis and Actinobacillus Spp. Notably, WGS results showed that the floR modules of the two types of plasmids could be transferred and integrated into the diverse Pasteurellaceae- origined plasmids. CONCLUSION: This study firstly reported the characterization of floR-carrying plasmids from A. indolicus and a non-virulent serovar of G. parasuis in pigs in China and elucidated the transmission mechanism of the floR resistance gene among the Pasteurellaceae family.
Assuntos
Actinobacillus , Antibacterianos , Animais , Suínos , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Tipagem de Sequências Multilocus , Filogenia , Plasmídeos/genética , Actinobacillus/genéticaRESUMO
In this work, a bioprocess for the fermentation of A. succinogenes for the production of succinic acid from glycerol was developed, employing a continuous bioreactor with recycle. Moreover, a new bioprocess model was constructed, based on an existing double substrate limitation model, which was validated with experimental results for a range of operating parameters. The model was used to successfully predict the dynamics of the continuous fermentation process and was subsequently employed in optimisation studies to compute the optimal conditions, dilution rate, reflux rate and feed glycerol concentration, that maximise the productivity of bio-succinic acid. In addition, a Pareto front for optimal volumetric productivity and glycerol conversion combinations was computed. Maximum volumetric productivity of 0.518 g/L/h, was achieved at the optimal computed conditions, which were experimentally validated. This is the highest bio-succinic acid productivity reported so far, for such a continuous bioprocess.
Assuntos
Actinobacillus , Glicerol , Ácido Succínico , Reatores Biológicos , FermentaçãoRESUMO
Actinobacillus pleuropneumoniae (APP) is the causative pathogen of porcine pleuropneumonia, a highly contagious respiratory disease in the pig industry. The increasingly severe antimicrobial resistance in APP urgently requires novel antibacterial alternatives for the treatment of APP infection. In this study, we investigated the effect of tea polyphenols (TP) against APP. MIC and MBC of TP showed significant inhibitory effects on bacteria growth and caused cellular damage to APP. Furthermore, TP decreased adherent activity of APP to the newborn pig tracheal epithelial cells (NPTr) and the destruction of the tight adherence junction proteins ß-catenin and occludin. Moreover, TP improved the survival rate of APP infected mice but also attenuated the release of the inflammation-related cytokines IL-6, IL-8, and TNF-α. TP inhibited activation of the TLR/MAPK/PKC-MLCK signaling for down-regulated TLR-2, TLR4, p-JNK, p-p38, p-PKC-α, and MLCK in cells triggered by APP. Collectively, our data suggest that TP represents a promising therapeutic agent in the treatment of APP infection.
Assuntos
Infecções por Actinobacillus , Actinobacillus pleuropneumoniae , Actinobacillus , Infecções por Mycoplasma , Pleuropneumonia , Doenças dos Suínos , Animais , Suínos , Camundongos , Pleuropneumonia/microbiologia , Receptor 4 Toll-Like/metabolismo , Junções Íntimas , Pulmão/microbiologia , Infecções por Actinobacillus/tratamento farmacológico , Infecções por Actinobacillus/microbiologia , Chá/metabolismo , Doenças dos Suínos/microbiologiaRESUMO
Actinobacillus equuli is mostly associated with disease in horses and is most widely known as the causative agent of sleepy foal disease. Even though existing phenotypic tools such as biochemical tests, 16S rRNA gene sequencing, and Matrix Assisted Laser Desorption Ionization Time of Flight Mass Spectrometry (MALDI-TOF MS) can be used to identify members of the Actinobacillus genus, these methods struggle to differentiate between certain species and do not allow strain, virulence, and antimicrobial susceptibility typing. Hence, we performed in-depth analysis of 24 equine Actinobacillus isolates using phenotypic identification and susceptibility testing on the one hand, and long-read nanopore whole genome sequencing on the other hand. This allowed to address strain divergence down to the whole genome single nucleotide polymorphism (SNP) level. While lowest resolution was observed for 16S rRNA gene classification, a new multi-locus sequence typing (MLST) scheme allowed proper classification up to the species level. Nevertheless, a SNP-level analysis was required to distinguish A. equuli subspecies equuli and haemolyticus. Our data provided first WGS data on Actinobacillus genomospecies 1, Actinobacillus genomospecies 2, and A. arthritidis, which allowed the identification of a new Actinobacillus genomospecies 1 field isolate. Also, in-depth characterization of RTX virulence genes provided information on the distribution, completeness, and potential complementary nature of the RTX gene operons within the Actinobacillus genus. Even though overall low prevalence of acquired resistance was observed, two plasmids were identified conferring resistance to penicillin-ampicillin-amoxicillin and chloramphenicol in one A. equuli strain. In conclusion our data delivered new insights in the use of long-read WGS in high resolution identification, virulence gene typing, and antimicrobial resistance (AMR) of equine Actinobacillus species.
Assuntos
Actinobacillus , Animais , Cavalos , Actinobacillus/genética , Antibacterianos , Tipagem de Sequências Multilocus/veterinária , RNA Ribossômico 16S/genética , Virulência , Farmacorresistência Bacteriana , Sequenciamento Completo do Genoma/veterináriaRESUMO
This work aimed to study the efficiency of nano- and micro- fiber membranes in immobilizing Actinobacillus succinogenes CCTCC M2012036 for succinic acid production. Among the four kinds of electrospun nanofiber membranes of cellulose acetate, chitosan, poly(vinyl alcohol) (PVA) and chitosan-PVA, the cellulose acetate nanofiber membrane-immobilized cells performed the best with a succinic acid concentration and yield to be 27.3 ± 3.5 g/L and 70.9 ± 5.8%. The cell-immobilized viscose microfiber membrane presented good reuse stability, and 17 batches of fermentation without activity loss were realized with the highest succinic acid yield of 83.20%. A microfiber membrane bioreactor was further constructed with the cell-immobilized viscose microfiber membrane to perform fermentation on a larger scale, and the concentration, yield and productivity of succinic acid were 73.20 g/L, 86.50% and 1.49 g/(Lâ h) using a fed-batch strategy, which were 124.30%, 127.60% and 124.2% of those obtained in the traditional fermenter. This study provided an approach for improving the practicality of biological succinic acid production.
Assuntos
Actinobacillus , Quitosana , Ácido Succínico , Reatores Biológicos , FermentaçãoRESUMO
The high production of acetic acid (AC) as a by-product leads to difficult separation and purification of succinic acid (SA) and increases production costs in SA fermentation by Actinobacillus succinogenes. NaHSO3 as a steering agent was used to reduce AC production. Herein, the optimum fermentation conditions were achieved by single-factor and orthogonal tests as follows: glucose 60 g/L; MgCO3 60 g/L; NaHSO3 0.15% (w/v); and NaHSO3 addition time, 8 h after inoculation. After optimization, the SA and AC contents were 44.42 and 5.73 g/L. The SA improved by 100.72%, the AC decreased by 21.18% compared with the unfermented. The acetate kinase activity decreased by 14.36% and acetyl-CoA content improved by 97.55% in the group of NaHSO3 addition compared with control check (CK). The mechanism of NaHSO3 is formation acetaldehyde-sodium bisulfite compound and reduction the activity of acetate kinase. These findings indicated a new way of using NaHSO3 as a steering agent to reduce AC generation and may help promote the development of SA industrial production.
Assuntos
Ácido Acético , Actinobacillus , Acetato Quinase , Fermentação , Ácido SuccínicoRESUMO
The potential of renewable energy application via direct electrode interaction for the production of bio-based chemicals is a promising technology. The utilization of extracellular energy in pure culture fermentations aims in intracellular redox balance regulation in order to improve fermentation efficiency. This work evaluates the impact of a bioelectrochemical system in succinic acid fermentation and the metabolic response of Actinobacillus succinogenes. The metabolic pathway regulation of A. succinogenes was evaluated via RNA expression of the key enzymes that participate in TCA cycle, pyruvate metabolism and oxidative phosphorylation. The genes that were significantly overexpressed in BES compared to non-BES were phosphoenolpyruvate carboxykinase (0.4-fold change), inorganic pyrophosphatase (2.3-fold change) and hydrogenase (2.2-fold change) and the genes that were significantly underexpressed were fumarase (-0.94-fold change), pyruvate kinase (-6.9-fold change), all subunits of fumarate reductase (-2.1 to -1.17-fold change), cytochromes I and II (-1.25 and -1.02-fold change, respectively) and two C4-carboxylic acid transporters.
Assuntos
Actinobacillus , Fermentação , Actinobacillus/genética , Actinobacillus/metabolismo , Redes e Vias Metabólicas , EletricidadeRESUMO
There is growing recognition that regionalization of bacterial colonization and immunity along the intestinal tract has an important role in health and disease. Yet, the mechanisms underlying intestinal regionalization and its dysregulation in disease are not well understood. This study found that regional epithelial expression of the transcription factor GATA4 controls bacterial colonization and inflammatory tissue immunity in the proximal small intestine by regulating retinol metabolism and luminal IgA. Furthermore, in mice without jejunal GATA4 expression, the commensal segmented filamentous bacteria promoted pathogenic inflammatory immune responses that disrupted barrier function and increased mortality upon Citrobacter rodentium infection. In celiac disease patients, low GATA4 expression was associated with metabolic alterations, mucosal Actinobacillus, and increased IL-17 immunity. Taken together, these results reveal broad impacts of GATA4-regulated intestinal regionalization on bacterial colonization and tissue immunity, highlighting an elaborate interdependence of intestinal metabolism, immunity, and microbiota in homeostasis and disease.
Assuntos
Infecções por Enterobacteriaceae , Fator de Transcrição GATA4 , Microbioma Gastrointestinal , Mucosa Intestinal , Animais , Humanos , Camundongos , Actinobacillus , Microbioma Gastrointestinal/imunologia , Fator de Transcrição GATA4/metabolismo , Imunidade nas Mucosas , Interleucina-17/imunologia , Interleucina-17/metabolismo , Mucosa Intestinal/imunologia , Mucosa Intestinal/microbiologia , Intestino Delgado , SimbioseRESUMO
This is a case report of sepsis caused by the species Actinobacillus suis/equuli in a male agriculture worker that ended fatally. The article also contains information on identification and results of antibiotic susceptibility testing. This is a rare case of human infection and probably the first case of a human being infected by this species in the Czech Republic.
Assuntos
Infecções por Actinobacillus , Actinobacillus equuli , Actinobacillus suis , Actinobacillus , Sepse , Humanos , Adulto , Masculino , Sepse/diagnósticoRESUMO
Vine shoots and surplus grape must were assessed as feedstocks for succinic acid production with Actinobacillus succinogenes and Basfia succiniproducens. After acidic and enzymatic hydrolysis, vine shoots released 35-40 g/L total sugars. Both bacterial species produced 18-21 g/L succinic acid from this hydrolysate in 120 h. Regarding grape must fermentation, A. succinogenes clearly outperformed B. succiniproducens. Yeast extract (a source of organic nitrogen and vitamins) was the only additional nutrient needed by A. succinogenes to grow on grape must. Under mathematically optimized conditions (145.7 g/L initial sugars and 24.9 g/L yeast extract), A. succinogenes generated 88.9 ± 1.4 g/L succinic acid in 96 h, reaching a succinic acid yield of 0.66 ± 0.01 g/g and a sugar consumption of 96.64 ± 0.30%. Substrate inhibition was not observed in grape musts with 125-150 g/L initial sugars, provided that an adequate amount of yeast extract was available for bacteria. Alternative nitrogen sources to yeast extract (red wine lees, white wine lees, urea, NH4Cl, and choline chloride) were not suitable for A. succinogenes in grape must. KEY POINTS: ⢠Vine shoots and surplus grape must were assessed for succinic acid bioproduction. ⢠Succinic acid bioproduction was 21 g/L with vine shoots and 89 g/L with grape must. ⢠Fermentation was efficient at high sugar loads if organic N supply was adequate.
Assuntos
Actinobacillus , Vitis , Fermentação , Nitrogênio , Ácido Succínico , AçúcaresRESUMO
Pneumonia is a significant disease of horses. Although pneumonia has traditionally been studied in racehorses, little information is available for non-racing horses. Non-racing horses that died with pulmonary lesions (n = 156) were available from cases submitted for autopsy from January 2015 to June 2020. Bronchopneumonia (35%), interstitial pneumonia (29%), embolic pneumonia (21%), granulomatous pneumonia (13%), and pleuritis (2%) were observed in the examined horses. Seventy-four horses died or were euthanized because of pulmonary diseases, and 82 horses died or were euthanized because of non-pulmonary causes but had lung lesions. Of the horses that died from pulmonary causes, the most common finding was bronchopneumonia, with abscesses and/or necrosis in the cranioventral aspect of the lung. Bacteria isolated from cases of bronchopneumonia were Streptococcus equi subsp. zooepidemicus (48.5%), Klebsiella pneumoniae (12.1%), and Actinobacillus equuli subsp. haemolyticus (9.1%). The most common extrapulmonary lesions responsible for death in horses that also had lesions in the lung were mainly in the gastrointestinal system (30%), multiple systems (septicemia and/or toxemia; 27%), and musculoskeletal system (12%). The main postmortem findings in cases of bronchopneumonia of non-racing horses were similar to those reported previously in racehorses. However, some non-racing horses also had interstitial and granulomatous pneumonia, patterns not described previously in racehorses in California, likely as a result of the inclusion of extended age categories for non-racing horses. We also found that the equine lung was frequently affected in cases of sepsis and gastrointestinal problems of infectious origin.
Assuntos
Broncopneumonia , Doenças dos Cavalos , Pneumonia , Streptococcus equi , Actinobacillus , Animais , Broncopneumonia/veterinária , Doenças dos Cavalos/epidemiologia , Doenças dos Cavalos/patologia , Cavalos , Pneumonia/veterinária , Estudos RetrospectivosRESUMO
The species of the genus Actinobacillus have so far been associated with specific animal hosts, and A. suis sensu stricto, an opportunistic pathogen of swine, is rarely isolated from ruminants. We describe here the isolation of A. suis sensu stricto from a newborn calf that died on a dairy farm in Japan. Identification of the isolate was performed by phenotypic and genotypic characterization, with the latter consisting of nucleotide sequence analyses of the 16S rRNA gene plus three housekeeping genes, rpoB, infB and recN.
Assuntos
Infecções por Actinobacillus , Actinobacillus suis , Actinobacillus , Doenças dos Suínos , Infecções por Actinobacillus/veterinária , Actinobacillus suis/genética , Animais , Filogenia , RNA Ribossômico 16S/genética , SuínosRESUMO
Interleukin 5 (IL-5) regulates the maturation, activation, proliferation and function of immune cells, and plays an important role in the inflammatory response induced by an allergy. However, its anti-pathogen effect is poorly understood currently, especially on pneumonia. Here, this study was designed to elucidate the immunological role of IL-5 in the infection of mice with Actinobacillus pleuropneumoniae (APP). We established an acute lung infection model of APP in IL-5 knockout mice (IL-5-/-) and wild-type mice (WT) through nasal infusion or intraperitoneal injection, compared the survival rate, clinical symptoms, lung bacterial load, proportion of various immune cells, immune molecular expression, and neutrophil germicidal ability through flow cytometry, RT-qPCR, ELISA and immunofluorescence. Compared to WT mice, the IL-5-/- mice had a lower survival rate, more severe clinical symptoms, significantly increased bacterial load, and inflammatory cell infiltration in the lung after APP infection. In an uninfected state, IL-5 deficiency decreased the number of M1 interstitial macrophages and CD14- monocytes, while after infection, IL-5 deficiency significantly reduced the M2 alveolar macrophages, and increased PMN-II cells in the lung. Furthermore, the expression of IL-10, IL-4, IL-33, TNF-α, iNOS in the lung was lower in IL-5-/- mice under an uninfected condition, and the secretion of IL-18 was significantly increased after infection. In addition, IL-5 deficiency decreased bactericidal ability by inhibiting the formation of neutrophil extracellular traps (NETs). Collectively, these results provide evidence that IL-5 can enhance the resistance of APP infection, and its anti-infection mechanism, implying new targets and ideas for APP or similar respiratory agents' prevention and treatment.
Assuntos
Infecções por Actinobacillus , Actinobacillus pleuropneumoniae , Actinobacillus , Armadilhas Extracelulares , Infecções por Mycoplasma , Mycoplasma , Pleuropneumonia , Doenças dos Roedores , Infecções por Actinobacillus/veterinária , Animais , Armadilhas Extracelulares/metabolismo , Interleucina-5/genética , Interleucina-5/metabolismo , Pulmão/microbiologia , Camundongos , Camundongos Knockout , Infecções por Mycoplasma/veterinária , Pleuropneumonia/microbiologia , Pleuropneumonia/veterináriaRESUMO
Integrated data from molecular and improved culturomics studies might offer holistic insights on gut microbiome dysbiosis triggered by xenobiotics, such as obesity and metabolic disorders. Bisphenol A (BPA), a dietary xenobiotic obesogen, was chosen for a directed culturing approach using microbiota specimens from 46 children with obesity and normal-weight profiles. In parallel, a complementary molecular analysis was carried out to estimate the BPA metabolising capacities. Firstly, catalogues of 237 BPA directed-cultured microorganisms were isolated using five selected media and several BPA treatments and conditions. Taxa from Firmicutes, Proteobacteria, and Actinobacteria were the most abundant in normal-weight and overweight/obese children, with species belonging to the genera Enterococcus, Escherichia, Staphylococcus, Bacillus, and Clostridium. Secondly, the representative isolated taxa from normal-weight vs. overweight/obese were grouped as BPA biodegrader, tolerant, or resistant bacteria, according to the presence of genes encoding BPA enzymes in their whole genome sequences. Remarkably, the presence of sporobiota and concretely Bacillus spp. showed the higher BPA biodegradation potential in overweight/obese group compared to normal-weight, which could drive a relevant role in obesity and metabolic dysbiosis triggered by these xenobiotics.
Assuntos
Compostos Benzidrílicos/efeitos adversos , Exposição Dietética/efeitos adversos , Microbioma Gastrointestinal/genética , Obesidade Infantil/microbiologia , Fenóis/efeitos adversos , Xenobióticos/efeitos adversos , Actinobacillus/efeitos dos fármacos , Estudos de Casos e Controles , Criança , Disbiose/microbiologia , Feminino , Firmicutes/efeitos dos fármacos , Humanos , Masculino , Fenótipo , Proteobactérias/efeitos dos fármacosRESUMO
Economical source of succinic acid (SA) is most sought-after as a key platform chemical for a wide range of applications. Low-cost production of bio-succinic acid (bio-SA) from a renewable biomass resource i.e., oil palm trunk (OPT) is reported in this paper. Apart from carbon source, nitrogen source and mineral salts are other important nutrients affecting microbial cell growth and bio-SA biosynthesis by Actinobacillus succinogenes 130Z. In order to access and optimize nutrient requirement of the latter two sources, their effects in terms of types and concentrations were investigated. The findings highlighted the importance of selecting proper nitrogen source in A. succinogenes fermentation. The possibility of producing bio-SA from OPT economically can be achieved through minimal supply of 5 g/L yeast extract compared to that generally supplemented 15 g/L with a similar yield (0.47 g/g). In addition, a higher bio-SA yield (0.49 g/g) was achieved without adding mineral salts, which could further reduce fermentation cost. The use of minimally supplemented hydrolysate resulted in 21.1 g/L of bio-SA with a satisfactory yield (0.58 g/g) in a batch bioreactor system with an estimated 56.4% in cost savings. Conclusively, OPT bagasse hydrolysate is a nutrient-rich feedstock that can be practically utilized for bio-SA production.
Assuntos
Sais , Ácido Succínico , Actinobacillus , Celulose , Fermentação , Minerais , Nitrogênio/metabolismo , Nutrientes , Ácido Succínico/metabolismoRESUMO
Succinic acid (SA) is a top platform chemical obtainable from biomass. The current study evaluated the potential of Actinobacillus succinogenes for SA production using xylose-rich hemicellulosic fractions of two important lignocellulosic feedstocks, olive pits (OP) and sugarcane bagasse (SCB) and the results were compared with pure xylose. Initial experiments were conducted in shake flask followed by batch and fed-batch cultivation in bioreactor. Further separation of SA from the fermented broth was carried out by adapting direct crystallisation method. During fed-batch culture, maximum SA titers of 36.7, 33.6, and 28.7 g/L was achieved on pure xylose, OP and SCB hydrolysates, respectively, with same conversion yield of 0.27 g/g. The recovery yield of SA accumulated on pure xylose, OP and SCB hydrolysates was 79.1, 76.5, and 75.2%, respectively. The results obtained are of substantial value and pave the way for development of sustainable SA biomanufacturing in an integrated biorefinery.
Assuntos
Actinobacillus , Ácido Succínico , Fermentação , XiloseRESUMO
An integrated biorefinery has been developed using winery wastes (grape pomace-GP, stalks-GS, wine lees-WL). Bacterial cellulose was produced from GP extracted free sugars. Grape-seed oil and polyphenols were extracted from GP. Experimental design was employed to optimize lignin removal (50.8%) from mixtures of remaining GP solids and GS via NaOH (1.19% w/v) treatment at 70°C for 30 min. Delignification liquid contained condensed tannins with 76% Stiasny number. Enzymatic hydrolysis produced a sugar-rich hydrolysate (40.2 g/L sugars). Ethanol, antioxidants, tartaric acid and nutrient-rich hydrolysate were produced from WL. The crude hydrolysates were used in fed-batch Actinobacillus succinogenes cultures for 37.2 g/L succinic acid production. The biorefinery produces 42.65 g bacterial cellulose, 24.3 g oil, 40.3 g phenolic-rich extract with 1.41 Antioxidant Activity Index, 80.2 g ethanol, 624.8 g crude tannin extract, 20.03 g tartaric acid and 157.8 g succinic acid from 1 kg of each waste stream.