1
|
Current Trends of Using Antimicrobials in Acute Watery Diarrhoea in Children Below 5 Years of Age at Paediatrics Outpatient Department of a Tertiary Care Hospital in Bangladesh. Mymensingh Med J 2024; 33:23-30. [PMID: 38163769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
Childhood diarrhoea is a major public health problem in developing countries like Bangladesh which is commonly caused by intestinal infection, mainly viral. Diarrhoea is causing second leading mortality in children below 5 years, where about 2 billion cases occur globally in each year. This study was proposed to evaluate the antimicrobials utilization pattern prescribed for AWD in children below 5 years of age, in a tertiary care hospital in Bangladesh. This record based, cross-sectional, descriptive type of observational study carried out at pharmacology department of Mymensingh Medical College. A total of 205 diarrhoeal patient's up to 5 years of age, attending the paediatric OPD from January 2021 to December 2021, were enrolled in the study. Out of 205 patients 182(88.8%) were prescribed antimicrobials. Azithromycin was the most frequently prescribed antimicrobial (60.0%) and among the antiprotozoals metronidazole was the prescribed most (24.9%). ORS and Zinc were prescribed in all patients (100%). Empirical excessive use of antibiotics was observed in this study. Emphasis on educational and training programs may help in a better and judicious use of drugs in children.
Collapse
|
2
|
Antibacterial Effects of Methanol Henna (Lawsone inermis) Leaf Extracts against Two Food Borne Infection Causing Pathogens: Gram-Positive Staphylococcus aureus and Gram Negative Klebsiella pneumoniae. Mymensingh Med J 2023; 32:1009-1014. [PMID: 37777894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/02/2023]
Abstract
Evaluation of the in vitro antibacterial activity of Methanol extracts isolated from Henna (Lawsonia inermis) leaf against two food born infection causing pathogens, gram-positive Staphylococcus aureus and gram-negative Klebsiella pneumoniae. This interventional study was carried out in the Department of Pharmacology and Therapeutics in collaboration with the Department of Microbiology, Mymensingh Medical College, Bangladesh from January 2021 to December 2021. The antibacterial activity was tested at different concentrations of Methanol Henna leaf extracts by using disc diffusion and broth dilution method. The extract was prepared by using solvents Methanol and 0.1% dimethyl sulfoxide (DMSO). The test microorganisms were also tested for their activity against a standard antibiotic Ciprofloxacin by broth dilution method and the result was compared with that of Methanol extracts. Methanol Henna Extracts (MHE) were used initially in nine different concentrations (2.5, 5, 10, 20, 50, 100, 200, 500 and 1000mg/ml) and later in selected concentrations as needed to confirm the more precise margin of antimicrobial sensitivity of the extracts. Among different concentrations of the MHE, 100mg/ml and above concentrations showed inhibitory effect against afore said bacteria. The MIC for Staphylococcus aureus and Klebsiella pneumoniae were 100mg/ml in MHE. The MIC of Ciprofloxacin was 1μg/ml against Staphylococcus aureus and 1.5μg/ml for Klebsiella pneumoniae. The MIC of Ciprofloxacin was the lowest in comparison to MICs of MHE for the test organisms. This study showed that Methanol Henna extracts demonstrated antibacterial effects against pathogens. From this study, it is clearly observed that there is definite antibacterial effect of the methanolic extract of Henna leaves (Lawsonia inermis) against Staphylococcus aureus and Klebsiella pneumoniae.
Collapse
|
3
|
Antibacterial Activities of Mint (Mentha piperita) Leaf Extracts (Aqueous) Against Two Food Borne infection causing pathogens: Staphylococcus aureus and Escherichia coli. Mymensingh Med J 2023; 32:659-665. [PMID: 37391956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/02/2023]
Abstract
Evaluation of the in vitro antibacterial activity of Aqueous extracts isolated from Mint (Mentha piperita) leaf against two food born infection causing pathogens, gram-positive Staphylococcus aureus and gram-negative Escherichia coli. This interventional study was carried out in the Department of Pharmacology and Therapeutics in collaboration with the Department of Microbiology, Mymensingh Medical College, Bangladesh from January 2021 to December 2021. The antibacterial activity was tested at different concentrations of Aqueous Mint leaf extracts by using disc diffusion & broth dilution method. The extract was prepared by using solvents Aqueous. The test microorganisms were also tested for their activity against a standard antibiotic Gentamicin by broth dilution method and the result was compared with that of Aqueous extracts. Aqueous extract of Mint leaves (AMLE) were used initially in eight different concentrations (25, 50, 100, 200, 400, 600, 800 and 1000μg/ml) and later in selected concentrations as needed to confirm the more precise margin of antimicrobial sensitivity of the extracts. Among different concentrations of the AMLE, 200μg/ml and above concentrations showed inhibitory effect against Staphylococcus aureus and 400μg/ml and above concentrations showed inhibitory effect against Escherichia coli. Minimum inhibitory concentration (MIC) for Staphylococcus aureus and Escherichia coli were 200 and 400μg/ml in AMLE respectively. The MIC of Gentamicin was 1μg/ml against Staphylococcus aureus and 1.5μg/ml against Escherichia coli. The MIC of Gentamicin was the lowest in comparison to MICs of AMLE for the test organisms. This study showed that Aqueous Mint extracts demonstrated antibacterial effects against food borne pathogens. It is clearly observed that there is definite antibacterial effect of the aqueous extract of Mint leaves against Staphylococcus aureus and Escherichia coli.
Collapse
|
4
|
Antibacterial Effects of Chloroform Henna (Lawsonia inermis) Leaf Extracts against Two Nosocomial Infection Causing Pathogens: Gram-positive Staphylococcus aureus and Gram-negative Klebsiella pneumoniae: A Comparative Study. Mymensingh Med J 2023; 32:620-626. [PMID: 37391949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/02/2023]
Abstract
Evaluation of the in vitro antibacterial activity of Chloroform extracts isolated from Henna (Lawsonia inermis) leaf against two nosocomial infection causing pathogens, gram-positive Staphylococcus aureus and gram-negative Klebsiella pneumoniae. This interventional study was carried out for the period of January 2021 to December 2021 in the Department of Pharmacology and Therapeutics in collaboration with the Department of Microbiology, Mymensingh Medical College, Bangladesh. The antibacterial activity was tested at different concentrations of Chloroform Henna leaf extracts by using disc diffusion and broth dilution method. The extract was prepared by using solvents chloroform and 0.1% Dimethyl sulfoxide (DMSO). The test microorganisms were also tested for their activity against a standard antibiotic Ciprofloxacin by broth dilution method and the result was compared with that of Chloroform extracts. Chloroform Henna Extracts (CHE) were used initially in nine different concentrations (2.5, 5, 10, 20, 50, 100, 200, 500 and 1000 mg/ml). Among different concentrations of the CHE, 100mg/ml and above concentrations showed inhibitory effect against Staphylococcus aureus and Klebsiella pneumoniae. The MIC for Staphylococcus aureus and Klebsiella pneumoniae were 100 and 200mg/ml in CHE respectively. The MIC of Ciprofloxacin was 1μg/ml against Staphylococcus aureus and 1.5μg/ml against Klebsiella pneumoniae. The MIC of Ciprofloxacin was the lowest in comparison to MICs of CHE for the test organisms. This study showed that Chloroform Henna extracts demonstrated antibacterial effects against food borne pathogens. It is clearly observed that there is definite antibacterial effect of the Chloroform extract of Henna leaves (Lawsonia inermis) against Staphylococcus aureus and Klebsiella pneumoniae.
Collapse
|
5
|
Antibacterial Effects of Methanolic Leaf Extracts of Henna (Lawsonia inermis) Against Two Most Common Pathogenic Organisms: Gram Positive Staphylococcus aureus and Gram-Negative Escherichia coli. Mymensingh Med J 2023; 32:296-302. [PMID: 37002737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/04/2023]
Abstract
Evaluation of the in vitro antibacterial activity of Methanolic extracts isolated from Henna (Lawsonia inermis) leaf against two nosocomial infection causing pathogens, gram-positive Staphylococcus aureus and gram-negative Escherichia coli. This interventional study was carried out during the period of January 2021 to December 2021 in the Department of Pharmacology and Therapeutics in collaboration with the Department of Microbiology, Mymensingh Medical College, Mymensingh, Bangladesh. The antibacterial activity was tested at different concentrations of Methanolic Henna leaf extracts by using disc diffusion and broth dilution method. The extract was prepared by using solvents Methanol and 0.1% DMSO (Dimethyl sulfoxide). The test microorganisms were also tested for their activity against a standard antibiotic Ciprofloxacin by broth dilution method and the result was compared with that of Methanolic leaf extracts. Methanolic Henna leaf Extracts (MHE) were used initially in nine different concentrations (2.5, 5, 10, 20, 50, 100, 200, 500 and 1000 mg/ml) and later in selected concentrations as needed to confirm the more precise margin of antimicrobial sensitivity of the extracts. Among different concentrations of the MHE, 100mg/ml and above concentrations showed inhibitory effect against aforesaid bacteria. The MIC for Staphylococcus aureus and Escherichia coli were 100 and 200 mg/ml in MHE respectively. The MIC of Ciprofloxacin was 1μg/ml against both Staphylococcus aureus and Escherichia coli. The MIC of Ciprofloxacin was the lowest in comparison to MICs of MHE for the test organisms. The present study showed that Methanol Henna extracts demonstrated antibacterial effects against nosocomial infection pathogens. From this study, it is clearly observed that there are definite antibacterial effects of the methanolic extract of Henna leaves (Lawsonia inermis) against Staphylococcus aureus and Escherichia coli.
Collapse
|
6
|
Itaconic acid production by Aspergillus terreus from glucose up to pilot scale and from corn stover and wheat straw hydrolysates using new manganese tolerant medium. BIOCATALYSIS AND AGRICULTURAL BIOTECHNOLOGY 2022. [DOI: 10.1016/j.bcab.2022.102418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
|
7
|
Optimization of xylitol production from xylose by a novel arabitol limited co-producing Barnettozyma populi NRRL Y-12728. Prep Biochem Biotechnol 2020; 51:761-768. [PMID: 33305654 DOI: 10.1080/10826068.2020.1855443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Xylitol is a widely marketed sweetener with good functionality and health-promoting properties. It can be synthetized by many yeast species in a one-step reduction of xylose. Arabinose is a common contaminant found in xylose and there is ongoing interest in finding biocatalysts that selectively produce xyltiol. From a screen of 99 yeasts, Barnettozyma populi Y-12728 was found to selectively produce xylitol from both mixed sugars and corn stover hemicellulosic hydrolysate. Here, fermentation conditions for xylitol production from xylose by B. populi were optimized. The medium for xylitol production was optimized through response surface methodology. The yeast produced 31.2 ± 0.4 g xylitol from xylose (50 g L-1) in 62 h using the optimized medium. The optimal pH for xylitol production was 6.0. Glucose (10 g L-1), acetic acid (6.0 g L-1), HMF (4 mM) and ethanol (2.0 g L-1) inhibited the xylitol production. The glucose inhibition was entirely mitigated by using a 2-stage aeration strategy, indicating that the yeast was inhibited by ethanol produced from glucose under low aeration. This culture strategy will greatly benefit xylitol production from hemicellulosic hydrolysates, which often contain glucose. This is the first report on optimization of xylitol production by a Barnettozyma species.
Collapse
|
8
|
Efficient itaconic acid production by Aspergillus terreus: Overcoming the strong inhibitory effect of manganese. Biotechnol Prog 2019; 36:e2939. [PMID: 31682331 DOI: 10.1002/btpr.2939] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 10/23/2019] [Accepted: 10/31/2019] [Indexed: 01/15/2023]
Abstract
Itaconic acid (IA), a building block platform chemical, is produced industrially by Aspergillus terreus utilizing glucose. Lignocellulosic biomass can serve as a low cost source of sugars for IA production. However, the fungus could not produce IA from dilute acid pretreated and enzymatically saccharified wheat straw hydrolyzate even at 100-fold dilution. Furfural, hydroxymethyl furfural and acetic acid were inhibitory, as is typical, but Mn2+ was particularly problematic for IA production. It was present in the hydrolyzate at a level that was 230 times over the inhibitory limit (50 ppb). Recently, it was found that PO4 3- limitation decreased the inhibitory effect of Mn2+ on IA production. In the present study, a novel medium was developed for production of IA by varying PO4 3- , Fe3+ and Cu2+ concentrations using response surface methodology, which alleviated the strong inhibitory effect of Mn2+ . The new medium contained 0.08 g KH2 PO4 , 3 g NH4 NO3 , 1 g MgSO4 ·7H2 O, 5 g CaCl2 ·2 H2 O, 0.83 mg FeCl3 ·6H2 O, 8 mg ZnSO4 ·7H2 O, and 45 mg CuSO4 ·5H2 O per liter. The fungus was able to produce IA very well in the presence of Mn2+ up to 100 ppm in the medium. This medium will be extremely useful for IA production in the presence of Mn2+ . This is the first report on the development of Mn2+ tolerant medium for IA production by A. terreus.
Collapse
|
9
|
Valorization of egg shell as a detoxifying and buffering agent for efficient polymalic acid production by Aureobasidium pullulans NRRL Y-2311-1 from barley straw hydrolysate. BIORESOURCE TECHNOLOGY 2019; 278:130-137. [PMID: 30684726 DOI: 10.1016/j.biortech.2018.12.119] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 12/29/2018] [Accepted: 12/31/2018] [Indexed: 06/09/2023]
Abstract
Stepwise formulation of a versatile and cost-effective medium based on barley straw hydrolysate and egg shell for efficient polymalic acid production by A. pullulans NRRL Y-2311-1 was carried out for the first time. The strain did not grow and produce polymalic acid when dilute acid pretreated barley straw hydrolysate (total fermentable sugars: 94.60 g/L; furfural: 1.01 g/L; hydroxymethylfurfural: 0.55 g/L; acetic acid: 5.06 g/L) was directly used in medium formulation without detoxification (e.g. charcoal pretreatment). When CaCO3 in the medium formulation was substituted with egg shell powder, efficient production of polymalic acid was achieved without a detoxification step. Utilization of 40 g/L of egg shell powder led to 43.54 g polymalic acid production per L with the productivity of 0.30 g/L/h and yield of 0.48 g/g. The bioprocess strategy used in this study can also be utilized for mass production of several other industrially important microbial organic acids and biomaterials.
Collapse
|
10
|
High solid fed‐batch butanol fermentation with simultaneous product recovery: Part II—process integration. Biotechnol Prog 2018; 34:967-972. [DOI: 10.1002/btpr.2643] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 04/13/2018] [Indexed: 11/11/2022]
|
11
|
Butanol production from sweet sorghum bagasse with high solids content: Part I-comparison of liquid hot water pretreatment with dilute sulfuric acid. Biotechnol Prog 2018; 34:960-966. [PMID: 29693794 DOI: 10.1002/btpr.2639] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 04/13/2018] [Indexed: 11/11/2022]
Abstract
In these studies, we pretreated sweet sorghum bagasse (SSB) using liquid hot water (LHW) or dilute H2 SO4 (2 g L-1 ) at 190°C for zero min (as soon as temperature reached 190°C, cooling was started) to reduce generation of sugar degradation fermentation inhibiting products such as furfural and hydroxymethyl furfural (HMF). The solids loading were 250-300 g L-1 . This was followed by enzymatic hydrolysis. After hydrolysis, 89.0 g L-1 sugars, 7.60 g L-1 acetic acid, 0.33 g L-1 furfural, and 0.07 g L-1 HMF were released. This pretreatment and hydrolysis resulted in the release of 57.9% sugars. This was followed by second hydrolysis of the fibrous biomass which resulted in the release of 43.64 g L-1 additional sugars, 2.40 g L-1 acetic acid, zero g L-1 furfural, and zero g L-1 HMF. In both the hydrolyzates, 86.3% sugars present in SSB were released. Fermentation of the hydrolyzate I resulted in poor acetone-butanol-ethanol (ABE) fermentation. However, fermentation of the hydrolyzate II was successful and produced 13.43 g L-1 ABE of which butanol was the main product. Use of 2 g L-1 H2 SO4 as a pretreatment medium followed by enzymatic hydrolysis resulted in the release of 100.6-93.8% (w/w) sugars from 250 to 300 g L-1 SSB, respectively. LHW or dilute H2 SO4 were used to economize production of cellulosic sugars from SSB. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 34:960-966, 2018.
Collapse
|
12
|
Correction: Evaluation of 19,460 Wheat Accessions Conserved in the Indian National Genebank to Identify New Sources of Resistance to Rust and Spot Blotch Diseases. PLoS One 2017; 12:e0175610. [PMID: 28384321 PMCID: PMC5383313 DOI: 10.1371/journal.pone.0175610] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
|
13
|
Biological pretreatment of corn stover withPhlebia brevisporaNRRL-13108 for enhanced enzymatic hydrolysis and efficient ethanol production. Biotechnol Prog 2017; 33:365-374. [DOI: 10.1002/btpr.2420] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 11/17/2016] [Indexed: 11/06/2022]
|
14
|
Production of xylitol by aConiochaeta ligniariastrain tolerant of inhibitors and defective in growth on xylose. Biotechnol Prog 2016; 32:606-12. [DOI: 10.1002/btpr.2259] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Revised: 03/03/2016] [Indexed: 11/07/2022]
|
15
|
Irradiation of Yarrowia lipolytica NRRL YB-567 creating novel strains with enhanced ammonia and oil production on protein and carbohydrate substrates. Appl Microbiol Biotechnol 2015; 99:9723-43. [PMID: 26272089 PMCID: PMC4628078 DOI: 10.1007/s00253-015-6852-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Revised: 07/12/2015] [Accepted: 07/15/2015] [Indexed: 01/05/2023]
Abstract
Increased interest in sustainable production of renewable diesel and other valuable bioproducts is redoubling efforts to improve economic feasibility of microbial-based oil production. Yarrowia lipolytica is capable of employing a wide variety of substrates to produce oil and valuable co-products. We irradiated Y. lipolytica NRRL YB-567 with UV-C to enhance ammonia (for fertilizer) and lipid (for biodiesel) production on low-cost protein and carbohydrate substrates. The resulting strains were screened for ammonia and oil production using color intensity of indicators on plate assays. Seven mutant strains were selected (based on ammonia assay) and further evaluated for growth rate, ammonia and oil production, soluble protein content, and morphology when grown on liver infusion medium (without sugars), and for growth on various substrates. Strains were identified among these mutants that had a faster doubling time, produced higher maximum ammonia levels (enzyme assay) and more oil (Sudan Black assay), and had higher maximum soluble protein levels (Bradford assay) than wild type. When grown on plates with substrates of interest, all mutant strains showed similar results aerobically to wild-type strain. The mutant strain with the highest oil production and the fastest doubling time was evaluated on coffee waste medium. On this medium, the strain produced 0.12 g/L ammonia and 0.20 g/L 2-phenylethanol, a valuable fragrance/flavoring, in addition to acylglycerols (oil) containing predominantly C16 and C18 residues. These mutant strains will be investigated further for potential application in commercial biodiesel production.
Collapse
|
16
|
Enhancement of xylose utilization from corn stover by a recombinant Escherichia coli strain for ethanol production. BIORESOURCE TECHNOLOGY 2015; 190:182-8. [PMID: 25958140 DOI: 10.1016/j.biortech.2015.04.079] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Revised: 04/21/2015] [Accepted: 04/23/2015] [Indexed: 05/27/2023]
Abstract
Effects of substrate-selective inoculum prepared by growing on glucose, xylose, arabinose, GXA (glucose, xylose, arabinose, 1:1:1) and corn stover hydrolyzate (dilute acid pretreated and enzymatically hydrolyzed, CSH) on ethanol production from CSH by a mixed sugar utilizing recombinant Escherichia coli (strain FBR5) were investigated. The initial ethanol productivity was faster for the seed grown on xylose followed by GXA, CSH, glucose and arabinose. Arabinose grown seed took the longest time to complete the fermentation. Delayed saccharifying enzyme addition in simultaneous saccharification and fermentation of dilute acid pretreated CS by the recombinant E. coli strain FBR5 allowed the fermentation to finish in a shorter time than adding the enzyme simultaneously with xylose grown inoculum. Use of substrate selective inoculum and fermenting pentose sugars first under glucose limited condition helped to alleviate the catabolite repression of the recombinant bacterium on ethanol production from lignocellulosic hydrolyzate.
Collapse
|
17
|
Process for Assembly and Transformation into Saccharomyces cerevisiae of a Synthetic Yeast Artificial Chromosome Containing a Multigene Cassette to Express Enzymes That Enhance Xylose Utilization Designed for an Automated Platform. ACTA ACUST UNITED AC 2015; 20:621-35. [PMID: 25720598 DOI: 10.1177/2211068215573188] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Indexed: 01/26/2023]
Abstract
A yeast artificial chromosome (YAC) containing a multigene cassette for expression of enzymes that enhance xylose utilization (xylose isomerase [XI] and xylulokinase [XKS]) was constructed and transformed into Saccharomyces cerevisiae to demonstrate feasibility as a stable protein expression system in yeast and to design an assembly process suitable for an automated platform. Expression of XI and XKS from the YAC was confirmed by Western blot and PCR analyses. The recombinant and wild-type strains showed similar growth on plates containing hexose sugars, but only recombinant grew on D-xylose and L-arabinose plates. In glucose fermentation, doubling time (4.6 h) and ethanol yield (0.44 g ethanol/g glucose) of recombinant were comparable to wild type (4.9 h and 0.44 g/g). In whole-corn hydrolysate, ethanol yield (0.55 g ethanol/g [glucose + xylose]) and xylose utilization (38%) for recombinant were higher than for wild type (0.47 g/g and 12%). In hydrolysate from spent coffee grounds, yield was 0.46 g ethanol/g (glucose + xylose), and xylose utilization was 93% for recombinant. These results indicate introducing a YAC expressing XI and XKS enhanced xylose utilization without affecting integrity of the host strain, and the process provides a potential platform for automated synthesis of a YAC for expression of multiple optimized genes to improve yeast strains.
Collapse
|
18
|
Pilot scale conversion of wheat straw to ethanol via simultaneous saccharification and fermentation. BIORESOURCE TECHNOLOGY 2015; 175:17-22. [PMID: 25459799 DOI: 10.1016/j.biortech.2014.10.060] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 10/09/2014] [Accepted: 10/10/2014] [Indexed: 06/04/2023]
Abstract
The production of ethanol from wheat straw (WS) by dilute acid pretreatment, bioabatement of fermentation inhibitors by a fungal strain, and simultaneous saccharification and fermentation (SSF) of the bio-abated WS to ethanol using an ethanologenic recombinant bacterium was studied at a pilot scale without sterilization. WS (124.2g/L) was pretreated with dilute H2SO4 in two parallel tube reactors at 160°C. The inhibitors were bio-abated by growing the fungus aerobically. The maximum ethanol produced by SSF of the bio-abated WS by the recombinant Escherichia coli FBR5 at pH 6.0 and 35°C was 36.0g/L in 83h with a productivity of 0.43gL(-1)h(-1). This value corresponds to an ethanol yield of 0.29g/g of WS which is 86% of the theoretical ethanol yield from WS. This is the first report on the production of ethanol by the recombinant bacterium from a lignocellulosic biomass at a pilot scale.
Collapse
|
19
|
Process integration for simultaneous saccharification, fermentation, and recovery (SSFR): production of butanol from corn stover using Clostridium beijerinckii P260. BIORESOURCE TECHNOLOGY 2014; 154:222-8. [PMID: 24398150 DOI: 10.1016/j.biortech.2013.11.080] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Revised: 11/26/2013] [Accepted: 11/29/2013] [Indexed: 05/23/2023]
Abstract
A simultaneous saccharification, fermentation, and recovery (SSFR) process was developed for the production of acetone-butanol-ethanol (AB or ABE), of which butanol is the main product, from corn stover employing Clostridium beijerinckii P260. Of the 86 g L(-1) corn stover provided, over 97% of the sugars were released during hydrolysis and these were fermented completely with an ABE productivity of 0.34 g L(-1)h(-1) and yield of 0.39. This productivity is higher than 0.31 g L(-1)h(-1) when using glucose as a substrate demonstrating that AB could be produced efficiently from lignocellulosic biomass. Acetic acid that was released from the biomass during pretreatment and hydrolysis was also used by the culture to produce AB. An average rate of generation of sugars during corn stover hydrolysis was 0.98 g L(-1)h(-1). In this system AB was recovered using vacuum, and as a result of this (simultaneous product recovery), 100% sugars were used by the culture.
Collapse
|
20
|
Alkaline Peroxide Pretreatment of Corn Stover for Enzymatic Saccharification and Ethanol Production. Ind Biotechnol (New Rochelle N Y) 2014. [DOI: 10.1089/ind.2013.0022] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
|
21
|
Abstract
INTRODUCTION Post-operative astigmatism is one of the most important causes for diminution of vision after trabeculectomy. OBJECTIVE To evaluate the induced corneal astigmatism following trabeculectomy with the use of 8-0 silk suture. MATERIALS AND METHODS A prospective interventional study was done including 100 consecutive eyes of 84 patients who underwent trabeculectomy with the use of 8-0 silk suture. The postoperative induced astigmatism on the 1st post-operative day, 3rd week and after 6 months was determined. STATISTICS Vector analysis was performed on the data using a computerized method for calculating the surgically induced astigmatism (SIA) for each eye at every time point postoperatively. In order to analyze group changes, we also performed vector decomposition which gave us a mathematical expression of the changes in astigmatism "with the rule" (WTR) or "against the rule" (ATR). RESULTS The mean age of all the patients was 53.31 11.39 years. The mean 1st post-operative surgically induced astigmatism (SIA) was 2.73 D ( 99 degree ) which reduced to 0.41 D ( 58 degree) at the 3rd week and 0.43 ( 21 degree) at 6 months. The mean WTR astigmatism was 4.46 D and ART astigmatism was 1.42 D on the 1st post-operative day which was significantly high ( p less than 0.0001). At the 3rd week and 6 months WTR astigmatism ( 1.40 D and 1.08D ) and ATR astigmatism (1.27 D and 1.10 D) showed no significant changes (p=0.69,0.97 respectively. CONCLUSION Trabeculectomy with the use of 8/0 silk sutures showed significantly high 1st post-operative day SIA which nevertheless perished fast to a minimum amount at just 3 weeks.
Collapse
|
22
|
Dilute sulfuric acid pretreatment of corn stover for enzymatic hydrolysis and efficient ethanol production by recombinant Escherichia coli FBR5 without detoxification. BIORESOURCE TECHNOLOGY 2013; 142:312-319. [PMID: 23747442 DOI: 10.1016/j.biortech.2013.05.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Revised: 04/30/2013] [Accepted: 05/02/2013] [Indexed: 06/02/2023]
Abstract
A pretreatment strategy for dilute H2SO4 pretreatment of corn stover was developed for the purpose of reducing the generation of inhibitory substances during pretreatment so that a detoxification step is not required prior to fermentation while maximizing sugar yield. The optimal conditions for pretreatment of corn stover (10%, w/v) were: 0.75% H2SO4, 160°C, and 0-5 min holding time. The conditions were chosen based on maximum glucose release after enzymatic hydrolysis, minimum loss of pentose sugars and minimum formation of sugar degradation products such as furfural and hydroxymethyl furfural. The pretreated corn stover after enzymatic saccharification generated 63.2 ± 2.2 and 63.7 ± 2.3 g total sugars per L at 0 and 5 min holding time, respectively. Furfural production was 0.45 ± 0.1 and 0.87 ± 0.4 g/L, respectively. The recombinant Escherichia coli strain FBR5 efficiently fermented non-detoxified corn stover hydrolyzate if the furfural content is <0.5 g/L.
Collapse
|
23
|
Response surface optimization of corn stover pretreatment using dilute phosphoric acid for enzymatic hydrolysis and ethanol production. BIORESOURCE TECHNOLOGY 2013; 130:603-12. [PMID: 23334017 DOI: 10.1016/j.biortech.2012.12.104] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Revised: 10/02/2012] [Accepted: 12/14/2012] [Indexed: 05/02/2023]
Abstract
Dilute H(3)PO(4) (0.0-2.0%, v/v) was used to pretreat corn stover (10%, w/w) for conversion to ethanol. Pretreatment conditions were optimized for temperature, acid loading, and time using central composite design. Optimal pretreatment conditions were chosen to promote sugar yields following enzymatic digestion while minimizing formation of furans, which are potent inhibitors of fermentation. The maximum glucose yield (85%) was obtained after enzymatic hydrolysis of corn stover pretreated with 0.5% (v/v) acid at 180°C for 15min while highest yield for xylose (91.4%) was observed from corn stover pretreated with 1% (v/v) acid at 160°C for 10min. About 26.4±0.1g ethanol was produced per L by recombinant Escherichia coli strain FBR5 from 55.1±1.0g sugars generated from enzymatically hydrolyzed corn stover (10%, w/w) pretreated under a balanced optimized condition (161.81°C, 0.78% acid, 9.78min) where only 0.4±0.0g furfural and 0.1±0.0 hydroxylmethyl furfural were produced.
Collapse
|
24
|
Genetically engineered Escherichia coli FBR5: part II. Ethanol production from xylose and simultaneous product recovery. Biotechnol Prog 2012; 28:1179-85. [PMID: 22736594 DOI: 10.1002/btpr.1584] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2012] [Revised: 06/05/2012] [Indexed: 11/08/2022]
Abstract
In these studies, concentrated xylose solution was fermented to ethanol using Escherichia coli FBR5 which can ferment both lignocellulosic sugars (hexoses and pentoses). E. coli FBR5 can produce 40-50 g L(-1) ethanol from 100 g L(-1) xylose in batch reactors. Increasing sugar concentration beyond this level results in the loss of sugar with the reactor effluent thus affecting the process yield adversely. In a nonintegrated system without simultaneous product removal more than 120 g L(-1) xylose was left unused of the 220 g L(-1) that was fed into the reactor. In contrast to this, application of simultaneous product removal by gas stripping was able to relieve product inhibition and the culture was able to use 216.6 g L(-1) xylose thus producing 140 g L(-1) (based on reactor volume) ethanol resulting in a product yield of 0.48. The product stream achieved an ethanol concentration up to 148.41 g L(-1). This process has potential for greatly improving the performance of E. coli FBR5 where the strain can ferment all the lignocellulosic sugars to ethanol and gas stripping can be applied to recover product.
Collapse
|
25
|
Hydrothermal pretreatment of sugarcane bagasse using response surface methodology improves digestibility and ethanol production by SSF. ACTA ACUST UNITED AC 2012; 39:439-47. [DOI: 10.1007/s10295-011-1051-3] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Accepted: 10/19/2011] [Indexed: 10/15/2022]
Abstract
Abstract
Sugarcane bagasse was characterized as a feedstock for the production of ethanol using hydrothermal pretreatment. Reaction temperature and time were varied between 160 and 200°C and 5–20 min, respectively, using a response surface experimental design. The liquid fraction was analyzed for soluble carbohydrates and furan aldehydes. The solid fraction was analyzed for structural carbohydrates and Klason lignin. Pretreatment conditions were evaluated based on enzymatic extraction of glucose and xylose and conversion to ethanol using a simultaneous saccharification and fermentation scheme. SSF experiments were conducted with the washed pretreated biomass. The severity of the pretreatment should be sufficient to drive enzymatic digestion and ethanol yields, however, sugars losses and especially sugar conversion into furans needs to be minimized. As expected, furfural production increased with pretreatment severity and specifically xylose release. However, provided that the severity was kept below a general severity factor of 4.0, production of furfural was below an inhibitory concentration and carbohydrate contents were preserved in the pretreated whole hydrolysate. There were significant interactions between time and temperature for all the responses except cellulose digestion. The models were highly predictive for cellulose digestibility (R2 = 0.8861) and for ethanol production (R2 = 0.9581), but less so for xylose extraction. Both cellulose digestion and ethanol production increased with severity, however, high levels of furfural generated under more severe pretreatment conditions favor lower severity pretreatments. The optimal pretreatment condition that gave the highest conversion yield of ethanol, while minimizing furfural production, was judged to be 190°C and 17.2 min. The whole hydrolysate was also converted to ethanol using SSF. To reduce the concentration of inhibitors, the liquid fraction was conditioned prior to fermentation by removing inhibitory chemicals using the fungus Coniochaeta ligniaria.
Collapse
|
26
|
Ethanol production from wheat straw by recombinant Escherichia coli strain FBR5 at high solid loading. BIORESOURCE TECHNOLOGY 2011; 102:10892-10897. [PMID: 21983410 DOI: 10.1016/j.biortech.2011.09.041] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2011] [Revised: 09/09/2011] [Accepted: 09/10/2011] [Indexed: 05/27/2023]
Abstract
Ethanol production by a recombinant bacterium from wheat straw (WS) at high solid loading by separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF) was studied. The yield of total sugars from dilute acid pretreated WS (150 g/L) after enzymatic saccharification was 86.3±1.5 g/L. The pretreated WS was bio-abated by growing a fungal strain aerobically in the liquid portion for 16 h. The recombinant Escherichia coli strain FBR5 produced 41.1±1.1 gethanol/L from non-abated WS hydrolyzate (total sugars, 86.6±0.3 g/L) in 168 h at pH7.0 and 35 °C. The bacterium produced 41.8±0.0 g ethanol/L in 120 h from the bioabated WS by SHF. It produced 41.6±0.7 g ethanol/L in 120 h from bioabated WS by fed-batch SSF. This is the first report of the production of above 4% ethanol from a lignocellulosic hydrolyzate by the recombinant bacterium.
Collapse
|
27
|
Comparison of separate hydrolysis and fermentation and simultaneous saccharification and fermentation processes for ethanol production from wheat straw by recombinant Escherichia coli strain FBR5. Appl Microbiol Biotechnol 2011; 92:865-74. [DOI: 10.1007/s00253-011-3600-0] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2011] [Revised: 09/02/2011] [Accepted: 09/03/2011] [Indexed: 10/17/2022]
|
28
|
Biotechnological production of mannitol and its applications. Appl Microbiol Biotechnol 2010; 89:879-91. [PMID: 21063702 DOI: 10.1007/s00253-010-2979-3] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2010] [Revised: 10/20/2010] [Accepted: 10/20/2010] [Indexed: 10/18/2022]
Abstract
Mannitol, a naturally occurring polyol (sugar alcohol), is widely used in the food, pharmaceutical, medical, and chemical industries. The production of mannitol by fermentation has become attractive because of the problems associated with its production chemically. A number of homo- and heterofermentative lactic acid bacteria (LAB), yeasts, and filamentous fungi are known to produce mannitol. In particular, several heterofermentative LAB are excellent producers of mannitol from fructose. These bacteria convert fructose to mannitol with 100% yields from a mixture of glucose and fructose (1:2). Glucose is converted to lactic acid and acetic acid, and fructose is converted to mannitol. The enzyme responsible for conversion of fructose to mannitol is NADPH- or NADH-dependent mannitol dehydrogenase (MDH). Fructose can also be converted to mannitol by using MDH in the presence of the cofactor NADPH or NADH. A two enzyme system can be used for cofactor regeneration with simultaneous conversion of two substrates into two products. Mannitol at 180 g l(-1) can be crystallized out from the fermentation broth by cooling crystallization. This paper reviews progress to date in the production of mannitol by fermentation and using enzyme technology, downstream processing, and applications of mannitol.
Collapse
|
29
|
Production of Candida antarctica lipase B gene open reading frame using automated PCR gene assembly protocol on robotic workcell and expression in an ethanologenic yeast for use as resin-bound biocatalyst in biodiesel production. ACTA ACUST UNITED AC 2010; 16:17-37. [PMID: 21609683 DOI: 10.1016/j.jala.2010.04.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2009] [Indexed: 11/27/2022]
Abstract
A synthetic Candida antarctica lipase B (CALB) gene open reading frame (ORF) for expression in yeast was constructed, and the lycotoxin-1 (Lyt-1) C3 variant gene ORF, potentially to improve the availability of the active enzyme at the surface of the yeast cell, was added in frame with the CALB ORF using an automated PCR assembly and DNA purification protocol on an integrated robotic workcell. Saccharomyces cerevisiae strains expressing CALB protein or CALB Lyt-1 fusion protein were first grown on 2% (w/v) glucose, producing 9.3 g/L ethanol during fermentation. The carbon source was switched to galactose for GAL1-driven expression, and the CALB and CALB Lyt-1 enzymes expressed were tested for fatty acid ethyl ester (biodiesel) production. The synthetic enzymes catalyzed the formation of fatty acid ethyl esters from ethanol and either corn or soybean oil. It was further demonstrated that a one-step-charging resin, specifically selected for binding to lipase, was capable of covalent attachment of the CALB Lyt-1 enzyme, and that the resin-bound enzyme catalyzed the production of biodiesel. High-level expression of lipase in an ethanologenic yeast strain has the potential to increase the profitability of an integrated biorefinery by combining bioethanol production with coproduction of a low-cost biocatalyst that converts corn oil to biodiesel.
Collapse
|
30
|
Production, Purification, and Properties of a Thermostable beta-Glucosidase from a Color Variant Strain of Aureobasidium pullulans. Appl Environ Microbiol 2010; 60:3774-80. [PMID: 16349415 PMCID: PMC201886 DOI: 10.1128/aem.60.10.3774-3780.1994] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A color variant strain of Aureobasidium pullulans (NRRL Y-12974) produced beta-glucosidase activity when grown in liquid culture on a variety of carbon sources, such as cellobiose, xylose, arabinose, lactose, sucrose, maltose, glucose, xylitol, xylan, cellulose, starch, and pullulan. An extracellular beta-glucosidase was purified 129-fold to homogeneity from the cell-free culture broth of the organism grown on corn bran. The purification protocol included ammonium sulfate treatment, CM Bio-Gel A agarose column chromatography, and gel filtrations on Bio-Gel A-0.5m and Sephacryl S-200. The beta-glucosidase was a glycoprotein with native molecular weight of 340,000 and was composed of two subunits with molecular weights of about 165,000. The enzyme displayed optimal activity at 75 degrees C and pH 4.5 and had a specific activity of 315 mumol . min . mg of protein under these conditions. The purified beta-glucosidase was active against p-nitrophenyl-beta-d-glucoside, cellobiose, cellotriose, cellotetraose, cellopentaose, cellohexaose, and celloheptaose, with K(m) values of 1.17, 1.00, 0.34, 0.36, 0.64, 0.68, and 1.65 mM, respectively. The enzyme activity was competitively inhibited by glucose (K(i) = 5.65 mM), while fructose, arabinose, galactose, mannose, and xylose (each at 56 mM) and sucrose and lactose (each at 29 mM) were not inhibitory. The enzyme did not require a metal ion for activity, and its activity was not affected by p-chloromercuribenzoate (0.2 mM), EDTA (10 mM), or dithiothreitol (10 mM). Ethanol (7.5%, vol/vol) stimulated the initial enzyme activity by 15%. Glucose production was enhanced by 7.9% when microcrystalline cellulose (2%, wt/vol) was treated for 48 h with a commercial cellulase preparation (5 U/ml) that was supplemented with the purified beta-glucosidase (0.21 U/ml) from A. pullulans.
Collapse
|
31
|
Comparison of pretreatment strategies for enzymatic saccharification and fermentation of barley straw to ethanol. N Biotechnol 2009; 27:10-6. [PMID: 19874923 DOI: 10.1016/j.nbt.2009.10.005] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2009] [Revised: 09/15/2009] [Accepted: 10/20/2009] [Indexed: 10/20/2022]
Abstract
Barley straw used in this study contained 34.3% cellulose, 23.0% hemicellulose and 13.3% lignin (moisture, 6.5%). Several pretreatments (dilute acid, lime and alkaline peroxide) and enzymatic saccharification procedures were evaluated for the conversion of barley straw to monomeric sugars. The maximum release of sugars (glucose, 384 mg; xylose, 187 mg; arabinose, 32 mg; total sugars, 604 mg/g; 94% of maximum theoretical sugar yield) from barley straw (10%, w/v) was obtained by alkaline peroxide (2.5% H(2)O(2), pH 11.5) pretreatment (35 degrees C, 24 hours) and enzymatic saccharification (45 degrees C, pH 5.0, 120 hours) after diluting 2 times before adding a cocktail of three commercial enzyme preparations (cellulase, beta-glucosidase and hemicellulase) each at the dose level of 0.15 ml/g of straw. Dilute acid and lime pretreatments followed by enzymatic saccharification generated 566 mg (88% yield) and 582 mg (91% yield) total sugars/g of barley straw, respectively. The yield of ethanol from the dilute acid pretreated and enzymatically saccharified barley straw hydrolyzate (23.7g sugars/L) was 11.4g/L (0.48g/g available sugars, 0.26g/g straw) by the mixed sugar utilizing recombinant Escherichia coli strain FBR5 in 17 hours. The ethanol yields were 11.4 and 11.9g/L from 24.4 and 26.2g sugars/L obtained from lime and alkaline peroxide pretreated barley straw, respectively. No inhibition of fermentation occurred by any of the three pretreatments under the conditions used.
Collapse
|
32
|
Automated Yeast Mating Protocol Using Open Reading Frames from Saccharomyces cerevisiae Genome to Improve Yeast Strains for Cellulosic Ethanol Production. ACTA ACUST UNITED AC 2009. [DOI: 10.1016/j.jala.2008.12.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Engineering the industrial ethanologen Saccharomyces cerevisiae to use pentose sugars from lignocellulosic biomass is critical for commercializing cellulosic fuel ethanol production. Approaches to engineer pentose-fermenting yeasts have required expression of additional genes. We implemented a high-throughput strategy to improve anaerobic growth on xylose and rate of ethanol production by evaluating overexpression of each native S. cerevisiae gene from a collection of haploid PJ69–4 MATa strains expressing the gene open reading frames (ORFs) mated to a haploid PJ69–4 MATalpha strain expressing the Piromyces sp.E2 xylose isomerase (XI) gene. The resulting 6113 diploid strains containing the XI gene and a different yeast gene ORF were screened for growth on xylose in anaerobic plate cultures using an integrated robotic workcell. Nine unique strains were isolated; two were found to no longer grow on glucose; seven were further evaluated for fermentation of alkaline peroxide pretreated enzymatically saccharified wheat straw hydrolysate. All successfully used glucose and xylose, consuming most of the glucose and a small amount of the xylose. Transforming the strains with an additional vector expressing xylulokinase gene did not improve anaerobic growth on xylose but improved glucose use and ethanol production on the hydrolysate, with three strains giving maximum ethanol production ≥ 14.0 g L −1 .
Collapse
|
33
|
Microbial production of xylitol from l-arabinose by metabolically engineered Escherichia coli. J Biosci Bioeng 2009; 107:506-11. [DOI: 10.1016/j.jbiosc.2008.12.017] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2008] [Revised: 12/25/2008] [Accepted: 12/25/2008] [Indexed: 10/20/2022]
|
34
|
Isolation of an operon involved in xylitol metabolism from a xylitol-utilizing Pantoea ananatis mutant. J Biosci Bioeng 2009; 106:337-44. [PMID: 19000608 DOI: 10.1263/jbb.106.337] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2008] [Accepted: 06/20/2008] [Indexed: 11/17/2022]
Abstract
An operon involved in cryptic xylitol metabolism of Pantoea ananatis was cloned by transposon tagging. A xylitol negative mutant with a transposon insertion in the xylitol 4-dehydrogenase gene (xdh) was isolated and genomic DNA around the transposon was sequenced. Consequently, six consecutive genes, xytB-G are located downstream of xdh in the same strand. These seven genes are cotranscribed as a single transcript in a P. ananatis xylitol-utilizing mutant, suggesting that they comprise an operon. In addition to xdh, xytF also encodes oxidoreductase that is a member of the short-chain dehydrogenase/reductase family. Recombinant Escherichia coli that heterologously expresses the Xdh protein converts xylitol to xylulose as expected. On the other hand, the recombinant XytF protein has activity with l-arabitol but not with xylitol. XytB, xytD and xytE have significant sequence similarities to genes encoding the substrate-binding, ATP-binding and permease subunits, respectively, of ATP-binding cassette transporters. Although the physiological role of the operon remains unknown, the operon appears to be involved in uptake and metabolism of a various sugar alcohols. A gene encoding a DeoR-type transcriptional regulator, xytR, is located upstream of the operon in the opposite strand and a single nucleotide substitution that could cause a nonsense mutation is present in the xytR gene of the xylitol-utilizing mutant. This result suggests that the product of xytR negatively controls expression of the operon like other DeoR regulators.
Collapse
|
35
|
Sessions 2 and 7: Advances in Microbial Science and Technology. Appl Biochem Biotechnol 2009; 153:11-2. [DOI: 10.1007/s12010-009-8609-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
36
|
Cloning, purification, and characterization of a thermostable α-l-arabinofuranosidase from Anoxybacillus kestanbolensis AC26Sari. Appl Microbiol Biotechnol 2008; 81:61-8. [DOI: 10.1007/s00253-008-1584-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2008] [Revised: 06/03/2008] [Accepted: 06/17/2008] [Indexed: 11/24/2022]
|
37
|
Dilute Acid Pretreatment, Enzymatic Saccharification, and Fermentation of Rice Hulls to Ethanol. Biotechnol Prog 2008; 21:816-22. [PMID: 15932261 DOI: 10.1021/bp049564n] [Citation(s) in RCA: 222] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Rice hulls, a complex lignocellulosic material with high lignin (15.38 +/- 0.2%) and ash (18.71 +/- 0.01%) content, contain 35.62 +/- 0.12% cellulose and 11.96 +/- 0.73% hemicellulose and has the potential to serve as a low-cost feedstock for production of ethanol. Dilute H2SO4 pretreatments at varied temperature (120-190 degrees C) and enzymatic saccharification (45 degrees C, pH 5.0) were evaluated for conversion of rice hull cellulose and hemicellulose to monomeric sugars. The maximum yield of monomeric sugars from rice hulls (15%, w/v) by dilute H2SO4 (1.0%, v/v) pretreatment and enzymatic saccharification (45 degrees C, pH 5.0, 72 h) using cellulase, beta-glucosidase, xylanase, esterase, and Tween 20 was 287 +/- 3 mg/g (60% yield based on total carbohydrate content). Under this condition, no furfural and hydroxymethyl furfural were produced. The yield of ethanol per L by the mixed sugar utilizing recombinant Escherichia colistrain FBR 5 from rice hull hydrolyzate containing 43.6 +/- 3.0 g fermentable sugars (glucose, 18.2 +/- 1.4 g; xylose, 21.4 +/- 1.1 g; arabinose, 2.4 +/- 0.3 g; galactose, 1.6 +/- 0.2 g) was 18.7 +/- 0.6 g (0.43 +/- 0.02 g/g sugars obtained; 0.13 +/- 0.01 g/g rice hulls) at pH 6.5 and 35 degrees C. Detoxification of the acid- and enzyme-treated rice hull hydrolyzate by overliming (pH 10.5, 90 degrees C, 30 min) reduced the time required for maximum ethanol production (17 +/- 0.2 g from 42.0 +/- 0.7 g sugars per L) by the E. coli strain from 64 to 39 h in the case of separate hydrolysis and fermentation and increased the maximum ethanol yield (per L) from 7.1 +/- 2.3 g in 140 h to 9.1 +/- 0.7 g in 112 h in the case of simultaneous saccharification and fermentation.
Collapse
|
38
|
Production of mannitol by Lactobacillus intermedius NRRL B-3693 in fed-batch and continuous cell-recycle fermentations. Process Biochem 2007. [DOI: 10.1016/j.procbio.2007.09.001] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
39
|
Butanol production from wheat straw hydrolysate using Clostridium beijerinckii. Bioprocess Biosyst Eng 2007; 30:419-27. [PMID: 17609986 DOI: 10.1007/s00449-007-0137-9] [Citation(s) in RCA: 178] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2007] [Accepted: 06/08/2007] [Indexed: 10/23/2022]
Abstract
In these studies, butanol (acetone butanol ethanol or ABE) was produced from wheat straw hydrolysate (WSH) in batch cultures using Clostridium beijerinckii P260. In control fermentation 48.9 g L(-1) glucose (initial sugar 62.0 g L(-1)) was used to produce 20.1 g L(-1) ABE with a productivity and yield of 0.28 g L(-1 )h(-1) and 0.41, respectively. In a similar experiment where WSH (60.2 g L(-1) total sugars obtained from hydrolysis of 86 g L(-1) wheat straw) was used, the culture produced 25.0 g L(-1) ABE with a productivity and yield of 0.60 g L(-1 )h(-1) and 0.42, respectively. These results are superior to the control experiment and productivity was improved by 214%. When WSH was supplemented with 35 g L(-1) glucose, a reactor productivity was improved to 0.63 g L(-1 )h(-1) with a yield of 0.42. In this case, ABE concentration in the broth was 28.2 g L(-1). When WSH was supplemented with 60 g L(-1) glucose, the resultant medium containing 128.3 g L(-1) sugars was successfully fermented (due to product removal) to produce 47.6 g L(-1) ABE, and the culture utilized all the sugars (glucose, xylose, arabinose, galactose, and mannose). These results demonstrate that C. beijerinckii P260 has excellent capacity to convert biomass derived sugars to solvents and can produce over 28 g L(-1) (in one case 41.7 g L(-1) from glucose) ABE from WSH. Medium containing 250 g L(-1) glucose resulted in no growth and no ABE production. Mixtures containing WSH + 140 g L(-1) glucose (total sugar approximately 200 g L(-1)) showed poor growth and poor ABE production.
Collapse
|
40
|
Production of D-arabitol by a newly isolated Zygosaccharomyces rouxii. J Ind Microbiol Biotechnol 2007; 34:519-23. [PMID: 17357803 DOI: 10.1007/s10295-007-0211-y] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2006] [Accepted: 02/04/2007] [Indexed: 11/28/2022]
Abstract
A newly isolated Zygosaccharomyces rouxii NRRL 27,624 produced D-arabitol as the main metabolic product from glucose. In addition, it also produced ethanol and glycerol. The optimal conditions were temperature 30 degrees C, pH 5.0, 350 rpm, and 5% inoculum. The yeast produced 83.4 +/- 1.1 g D-arabitol from 175 +/- 1.1 g glucose per liter at pH 5.0, 30 degrees C, and 350 rpm in 240 h with a yield of 0.48 g/g glucose. It also produced D-arabitol from fructose, galactose, and mannose. The yeast produced D-arabitol and xylitol from xylose and also from a mixture of xylose and xylulose. Resting yeast cells produced 63.6 +/- 1.9 g D-arabitol from 175 +/- 1.8 g glucose per liter in 210 h at pH 5.0, 30 degrees C and 350 rpm with a yield of 0.36 g/g glucose. The yeast has potential to be used for production of xylitol from glucose via D-arabitol route.
Collapse
|
41
|
Purification and characterization of a highly thermostable α-l-Arabinofuranosidase from Geobacillus caldoxylolyticus TK4. Appl Microbiol Biotechnol 2007; 75:813-20. [PMID: 17361432 DOI: 10.1007/s00253-007-0884-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2007] [Revised: 02/07/2007] [Accepted: 02/08/2007] [Indexed: 10/23/2022]
Abstract
The gene encoding an alpha-L: -arabinofuranosidase from Geobacillus caldoxylolyticus TK4, AbfATK4, was isolated, cloned, and sequenced. The deduced protein had a molecular mass of about 58 kDa, and analysis of its amino acid sequence revealed significant homology and conservation of different catalytic residues with alpha-L: -arabinofuranosidases belonging to family 51 of the glycoside hydrolases. A histidine tag was introduced at the N-terminal end of AbfATK4, and the recombinant protein was expressed in Escherichia coli BL21, under control of isopropyl-beta-D-thiogalactopyranoside-inducible T7 promoter. The enzyme was purified by nickel affinity chromatography. The molecular mass of the native protein, as determined by gel filtration, was about 236 kDa, suggesting a homotetrameric structure. AbfATK4 was active at a broad pH range (pH 5.0-10.0) and at a broad temperature range (40-85 degrees C), and it had an optimum pH of 6.0 and an optimum temperature of 75-80 degrees C. The enzyme was more thermostable than previously described arabinofuranosidases and did not lose any activity after 48 h incubation at 70 degrees C. The protein exhibited a high level of activity with p-nitrophenyl-alpha-L: -arabinofuranoside, with apparent K (m) and V (max) values of 0.17 mM and 588.2 U/mg, respectively. AbfATK4 also exhibited a low level of activity with p-nitrophenyl-beta-D: -xylopyranoside, with apparent K (m) and V (max) values of 1.57 mM and 151.5 U/mg, respectively. AbfATK4 released L: -arabinose only from arabinan and arabinooligosaccharides. No endoarabinanase activity was detected. These findings suggest that AbfATK4 is an exo-acting enzyme.
Collapse
|
42
|
Abstract
Acetone, butanol, and ethanol (ABE) were produced from corn fiber arabinoxylan (CFAX) and CFAX sugars (glucose, xylose, galactose, and arabinose) using Clostridium acetobutylicum P260. In mixed sugar (glucose, xylose, galactose, and arabinose) fermentation, the culture preferred glucose and arabinose over galactose and xylose. Under the experimental conditions, CFAX (60 g/L) was not fermented until either 5 g/L xylose or glucose plus xylanase enzyme were added to support initial growth and fermentation. In this system, C. acetobutylicum produced 9.60 g/L ABE from CFAX and xylose. This experiment resulted in a yield and productivity of 0.41 and 0.20 g/L x h, respectively. In the integrated hydrolysis, fermentation, and recovery process, 60 g/L CFAX and 5 g/L xylose produced 24.67 g/L ABE and resulted in a higher yield (0.44) and a higher productivity (0.47 g/L x h). CFAX was hydrolyzed by xylan-hydrolyzing enzymes, and ABE were recovered by gas stripping. This investigation demonstrated that integration of hydrolysis of CFAX, fermentation to ABE, and recovery of ABE in a single system is an economically attractive process. It is suggested that the culture be further developed to hydrolyze CFAX and utilize all xylan sugars simultaneously. This would further increase productivity of the reactor.
Collapse
|
43
|
Ethanol production from alkaline peroxide pretreated enzymatically saccharified wheat straw. Biotechnol Prog 2006; 22:449-53. [PMID: 16599561 DOI: 10.1021/bp050310r] [Citation(s) in RCA: 184] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Wheat straw used in this study contained 44.24 +/- 0.28% cellulose and 25.23 +/- 0.11% hemicellulose. Alkaline H(2)O(2) pretreatment and enzymatic saccharification were evaluated for conversion of wheat straw cellulose and hemicellulose to fermentable sugars. The maximum yield of monomeric sugars from wheat straw (8.6%, w/v) by alkaline peroxide pretreatment (2.15% H(2)O(2), v/v; pH 11.5; 35 degrees C; 24 h) and enzymatic saccharification (45 degrees C, pH 5.0, 120 h) by three commercial enzyme preparations (cellulase, beta-glucosidase, and xylanase) using 0.16 mL of each enzyme preparation per g of straw was 672 +/- 4 mg/g (96.7% yield). During the pretreatment, no measurable quantities of furfural and hydroxymethyl furfural were produced. The concentration of ethanol (per L) from alkaline peroxide pretreated enzyme saccharified wheat straw (66.0 g) hydrolyzate by recombinant Escherichia coli strain FBR5 at pH 6.5 and 37 degrees C in 48 h was 18.9 +/- 0.9 g with a yield of 0.46 g per g of available sugars (0.29 g/g straw). The ethanol concentration (per L) was 15.1 +/- 0.1 g with a yield of 0.23 g/g of straw in the case of simultaneous saccharification and fermentation by the E. coli strain at pH 6.0 and 37 degrees C in 48 h.
Collapse
|
44
|
Effect of salt nutrients on mannitol production by Lactobacillus intermedius NRRL B-3693. J Ind Microbiol Biotechnol 2006; 33:887-90. [PMID: 16736171 DOI: 10.1007/s10295-006-0140-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2005] [Accepted: 04/16/2006] [Indexed: 10/24/2022]
Abstract
The effects of four salt nutrients (ammonium citrate, sodium phosphate, magnesium sulfate, and manganese sulfate) on the production of mannitol by Lactobacillus intermedius NRRL B-3693 in a simplified medium containing 300 g fructose, 5 g soy peptone, and 50 g corn steep liquor per liter in pH-controlled fermentation at 5.0 at 37 degrees C were evaluated using a fractional factorial design. Only manganese sulfate was found to be essential for mannitol production. Added manganese sulfate concentration of 0.033 g/l was found to support maximum production. The bacterium produced 200.6 +/- 0.2 g mannitol, 61.9 +/- 0.1 g lactic acid, and 40.4 +/- 0.3 g acetic acid from 300 g fructose per liter in 67 h.
Collapse
|
45
|
A low-cost medium for mannitol production by Lactobacillus intermedius NRRL B-3693. Appl Microbiol Biotechnol 2006; 72:676-80. [PMID: 16534610 DOI: 10.1007/s00253-006-0364-z] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2005] [Revised: 01/26/2006] [Accepted: 02/01/2006] [Indexed: 10/24/2022]
Abstract
The production of mannitol by Lactobacillus intermedius NNRL B-3693 using molasses as an inexpensive carbon source was evaluated. The bacterium produced mannitol (104 g/l) from molasses and fructose syrups (1:1; total sugars, 150 g/l; fructose:glucose 4:1) in 16 h. Several kinds of inexpensive organic and inorganic nitrogen sources and corn steep liquor were evaluated for their potential to replace more expensive nitrogen sources derived from Bacto-peptone and yeast extract. Soy peptone D (5 g/l) and corn steep liquor (50 g/l) were found to be suitable substitutes for Bacto-peptone (5 g/l) and Bacto-yeast extract (5 g/l), respectively. The bacterium produced 105 g mannitol per liter from the molasses and fructose syrup (1:1, total sugars 150 g/l; fructose:glucose 4:1) in 22 h using a combination of soy peptone D (5 g/l) and corn steep liquor (50 g/l). This is the first report on the production of mannitol by fermentation using molasses and corn steep liquor.
Collapse
|
46
|
|
47
|
Pretreatment and enzymatic saccharification of corn fiber. Appl Biochem Biotechnol 2005; 76:65-77. [PMID: 15304728 DOI: 10.1385/abab:76:2:65] [Citation(s) in RCA: 125] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/1998] [Accepted: 09/10/1998] [Indexed: 11/11/2022]
Abstract
Corn fiber consists of about 20% starch, 14% cellulose, and 35% hemicellulose, and has the potential to serve as a low-cost feedstock for production of fuel ethanol. Several pretreatments (hot water, alkali, and dilute acid) and enzymatic saccharification procedures were evaluated for the conversion of corn fiber starch, cellulose, and hemicellulose to monomeric sugars. Hot water pretreatment (121 degrees C, 1 h) facilitated the enzymatic saccharification of starch and cellulose but not hemicellulose. Hydrolysis of corn fiber pretreated with alkali under similar conditions by enzymatic means gave similar results. Hemicellulose and starch components were converted to monomeric sugars by dilute H2SO4 pretreatment (0.5-1.0%, v/v) at 121 degrees C. Based on these findings, a method for pretreatment and enzymatic saccharification of corn fiber is presented. It involves the pretreatment of corn fiber (15% solid, w/v) with dilute acid (0.5% H2SO4, v/v) at 121 degrees C for 1 h, neutralization to pH 5.0, then saccharification of the pretreated corn fiber material with commercial cellulase and beta-glucosidase preparations. The yield of monomeric sugars from corn fiber was typically 85-100% of the theoretical yield.
Collapse
|
48
|
Profile of Enzyme Production by Trichoderma reesei Grown on Corn Fiber Fractions. Appl Biochem Biotechnol 2005. [DOI: 10.1385/abab:121:1-3:0321] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
49
|
Profile of enzyme production by Trichoderma reesei grown on corn fiber fractions. Appl Biochem Biotechnol 2005; 121-124:321-34. [PMID: 15917610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Corn fiber is the fibrous by-product of wet-mill corn processing. It typically consists of about 20% starch, 14% cellulose, and 30% hemicellulose in the form of arabinoxylan. Crude corn fiber (CCF) was fractionated into de-starched corn fiber (DSCF), corn fiber with cellulose (CFC) enriched, and corn fiber arabinoxylan (CFAX), and these fractions were evaluated as substrates for enzyme production by Trichoderma reesei. T. reesei QM9414 and Rut C-30 grew on CCF, DSCF, CFC, or CFAX and secreted a number of hydrolytic enzymes. The enzymes displayed synergism with commercial cellulases for corn fiber hydrolysis.
Collapse
|
50
|
Purification and characterization of a novel mannitol dehydrogenase from Lactobacillus intermedius. Biotechnol Prog 2004; 20:537-42. [PMID: 15059000 DOI: 10.1021/bp034277p] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Mannitol 2-dehydrogenase (MDH) catalyzes the pyridine nucleotide dependent reduction of fructose to mannitol. Lactobacillus intermedius (NRRL B-3693), a heterofermentative lactic acid bacterium (LAB), was found to be an excellent producer of mannitol. The MDH from this bacterium was purified from the cell extract to homogeneity by DEAE Bio-Gel column chromatography, gel filtration on Bio-Gel A-0.5m gel, octyl-Sepharose hydrophobic interaction chromatography, and Bio-Gel Hydroxyapatite HTP column chromatography. The purified enzyme (specific activity, 331 U/mg protein) was a heterotetrameric protein with a native molecular weight (MW) of about 170 000 and subunit MWs of 43 000 and 34 500. The isoelectric point of the enzyme was at pH 4.7. Both subunits had the same N-terminal amino acid sequence. The optimum temperature for the reductive action of the purified MDH was at 35 degrees C with 44% activity at 50 degrees C and only 15% activity at 60 degrees C. The enzyme was optimally active at pH 5.5 with 50% activity at pH 6.5 and only 35% activity at pH 5.0 for reduction of fructose. The optimum pH for the oxidation of mannitol to fructose was 7.0. The purified enzyme was quite stable at pH 4.5-8.0 and temperature up to 35 degrees C. The K(m) and V(max) values of the enzyme for the reduction of fructose to mannitol were 20 mM and 396 micromol/min/mg protein, respectively. It did not have any reductive activity on glucose, xylose, and arabinose. The activity of the enzyme on fructose was 4.27 times greater with NADPH than NADH as cofactor. This is the first highly NADPH-dependent MDH (EC 1.1.1.138) from a LAB. Comparative properties of the enzyme with other microbial MDHs are presented.
Collapse
|