scholarly journals Production ofN-Acetyl-d-Neuraminic Acid by Use of an Efficient Spore Surface Display System

2011 ◽  
Vol 77 (10) ◽  
pp. 3197-3201 ◽  
Author(s):  
Xiaoman Xu ◽  
Chao Gao ◽  
Xifeng Zhang ◽  
Bin Che ◽  
Cuiqing Ma ◽  
...  
Keyword(s):  
Surface Display ◽  
Value Added ◽  
Neuraminic Acid ◽  
High Yield ◽  
Permeability Barrier ◽  
Chemical Production ◽  
High Concentration ◽  
Suitable Alternative ◽  
Content Type ◽  
Whole Cells

ABSTRACTProduction ofN-acetyl-d-neuraminic acid (Neu5Ac) via biocatalysis is traditionally conducted using isolated enzymes or whole cells. The use of isolated enzymes is restricted by the time-consuming purification process, whereas the application of whole cells is limited by the permeability barrier presented by the microbial cell membrane. In this study, a novel type of biocatalyst, Neu5Ac aldolase presented on the surface ofBacillus subtilisspores, was used for the production of Neu5Ac. Under optimal conditions, Neu5Ac at a high concentration (54.7 g liter−1) and a high yield (90.2%) was obtained under a 5-fold excess of pyruvate overN-acetyl-d-mannosamine. The novel biocatalyst system, which is able to express and immobilize the target enzyme simultaneously on the surface ofB. subtilisspores, represents a suitable alternative for value-added chemical production.

scholarly journals A New Strategy for Production of 5-Aminolevulinic Acid in Recombinant Corynebacterium glutamicum with High Yield

2016 ◽  
Vol 82 (9) ◽  
pp. 2709-2717 ◽  
Author(s):  
Peng Yang ◽  
Wenjing Liu ◽  
Xuelian Cheng ◽  
Jing Wang ◽  
Qian Wang ◽  
...  
Keyword(s):  
Amino Acid ◽  
Corynebacterium Glutamicum ◽  
Recombinant Strain ◽  
Aminolevulinic Acid ◽  
Value Added ◽  
High Yield ◽  
Two Stage ◽  
Content Type ◽  
Nonprotein Amino Acid ◽  
The Future

ABSTRACT5-Aminolevulinic acid (ALA), a nonprotein amino acid involved in tetrapyrrole synthesis, has been widely applied in agriculture, medicine, and food production. Many engineered metabolic pathways have been constructed; however, the production yields are still low. In this study, several 5-aminolevulinic acid synthases (ALASs) from different sources were evaluated and compared with respect to their ALA production capacities in an engineeredCorynebacterium glutamicumCgS1 strain that can accumulate succinyl-coenzyme A (CoA). A codon-optimized ALAS fromRhodobacter capsulatusSB1003 displayed the best potential. Recombinant strain CgS1/pEC-SB produced 7.6 g/liter ALA using a mineral salt medium in a fed-batch fermentation mode. Employing two-stage fermentation, 12.46 g/liter ALA was produced within 17 h, with a productivity of 0.73 g/liter/h, in recombinantC. glutamicum. Through overexpression of the heterologous nonspecific ALA exporter RhtA fromEscherichia coli, the titer was further increased to 14.7 g/liter. This indicated that strain CgS1/pEC-SB-rhtA holds attractive industrial application potential for the future.IMPORTANCEIn this study, a two-stage fermentation strategy was used for production of the value-added nonprotein amino acid 5-aminolevulinic acid from glucose and glycine in a generally recognized as safe (GRAS) host,Corynebacterium glutamicum. The ALA titer represented the highest in the literature, to our knowledge. This high production capacity, combined with the potential easy downstream processes, made the recombinant strain an attractive candidate for industrial use in the future.

scholarly journals Efficient Production of 2-Oxobutyrate from 2-Hydroxybutyrate by Using Whole Cells of Pseudomonas stutzeri Strain SDM

2010 ◽  
Vol 76 (5) ◽  
pp. 1679-1682 ◽  
Author(s):  
Chao Gao ◽  
Wen Zhang ◽  
Chuanjuan Lv ◽  
Lixiang Li ◽  
Cuiqing Ma ◽  
...  
Keyword(s):  
Pseudomonas Stutzeri ◽  
High Yield ◽  
Efficient Production ◽  
Optimal Conditions ◽  
High Concentration ◽  
Whole Cells ◽  
Food Industries ◽  
Important Intermediate ◽  
Lactate Dehydrogenases ◽  
Biocatalytic Process

ABSTRACT 2-Oxobutyrate is an important intermediate in the chemical, drug, and food industries. Whole cells of Pseudomonas stutzeri SDM, containing NAD-independent lactate dehydrogenases, effectively converted 2-hydroxybutyrate into 2-oxobutyrate. Under optimal conditions, the biocatalytic process produced 2-oxobutyrate at a high concentration (44.4 g liter−1) and a high yield (91.5%).

scholarly journals Recovery of Value-Added Products from Hydrothermal Carbonization of Sewage Sludge

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Pannarai Saetea ◽  
Nakorn Tippayawong
Keyword(s):  
Sewage Sludge ◽  
Thermal Processing ◽  
Adsorption Property ◽  
Value Added ◽  
Hydrothermal Carbonization ◽  
Chemical Production ◽  
High Concentration ◽  
Liquid Phases ◽  
Closed Reactor ◽  
Value Added Products

This paper is about the conversion of wet waste stream into valuable products via thermal processing. Hydrothermal carbonization of sewage sludge was carried out at 200°C and 2.1 MPa in a closed reactor for 1–6 h. Main products were in solid and liquid phases. The resulting hydrochar was shown to have H/C and O/C ratios moving towards natural lignite, improved energetic content, and adsorption property in terms of iodine number. The aqueous solution was found to contain high concentration of plant food nutrients, especially nitrogen and potassium. They may be desirable for subsequent fuel and chemical production as well as applications in agriculture. The study shows that valuable products can be generated successfully from sewage sludge using hydrothermal carbonization.

Socioeconomic effects of pension spending: evidence from Spain

2020 ◽  
Vol 47 (5) ◽  
pp. 599-617
Author(s):  
Fernando Bermejo ◽  
Eladio Febrero ◽  
Andre Fernandes Tomon Avelino
Keyword(s):  
Peer Review ◽  
Social Protection ◽  
Pension System ◽  
Decomposition Analysis ◽  
Value Added ◽  
Total Output ◽  
Alternative View ◽  
Input Output ◽  
Structural Decomposition Analysis ◽  
Content Type

PurposeThe purpose of this study is to provide broader understanding of the significant role that the pension system has in the Spanish economy by estimating the sectoral production, employment and income sustained by pensioners' consumption.Design/methodology/approachBased on input–output tables by the World Input–Output Database and consumption data from the Household Budget Survey by the Spanish Statistical Office, a demoeconomic model is applied to quantify the direct impacts, indirect impacts from interindustry links and induced impacts from income–consumption connections over a nine-year period (2006–2014). Then, the factors driving the evolution of total output, employment and value added during such period have been examined by using structural decomposition analysis.FindingsThe growing participation of consumption by pensioner households in final demand had proven crucial during the 2008 crisis to alleviate the negative trend in production and employment derived from the collapse in consumption suffered by the rest of households.Practical implicationsDetermining the underlying factors driving changes in both employment and income during the 2008 crisis can be of interest in political decision-making on the sustainability of the Spanish pension system.Social implicationsThe results of estimating both the employment and income supported by pensioners' consumption reveal the significant stabilizing effect of the public spending on pensions, particularly during the 2008 crisis.Originality/valueThe current Spanish approach of attaining the pension system sustainability by merely reducing social protection costs ignores the adverse consequences of a lower pensioners' demand. This paper addresses an alternative view in which pension spending is not considered a burden on economic growth but rather a means of improving the level of production and employment.Peer reviewThe peer review history for this article is available at: https://publons.com/publon/10.1108/IJSE-01-2019-0047

Utilizing a systematic literature review to develop an integrated framework for information and knowledge management systems

2017 ◽  
Vol 47 (2) ◽  
pp. 250-264 ◽  
Author(s):  
Chulatep Senivongse ◽  
Alex Bennet ◽  
Stefania Mariano
Keyword(s):  
Knowledge Management ◽  
Literature Review ◽  
Systematic Literature Review ◽  
Value Added ◽  
Specific Area ◽  
Management Systems ◽  
Knowledge Management Systems ◽  
Content Type ◽  
Integrated Framework ◽  
Information And Knowledge Management

Purpose The purpose of this paper is to demonstrate the value of using a systematic literature review to develop an integrated framework for information and knowledge management systems. Design/methodology/approach First, the systematic literature review method is introduced, differentiating it from traditional literature reviews in terms of value-added and limitations. Second, this methodology is used in a research application focused on absorptive capacity internal capabilities with regard to the processes of acquisition, assimilation, transformation and exploitation. Third, an integrated framework for information and knowledge management systems is developed from this application. Findings The systematic literature review approach provides a rigor that can assist in reducing researcher bias while simultaneously enabling the definition of a precise scope of review, with a clear explanation of selection criteria with the objective to find and review all the studies that are relevant to the search definitions. As a research method, it effectively supports a qualitative, quantitative or mixed methodology. Research limitations/implications This methodology was applied to one specific area of research. Specific limitations include the availability of articles in subscribed databases and the analytical capabilities of the tools used for text mining and analytics. Originality/value This paper demonstrates the usefulness of the systematic literature review methodology in developing an integrated framework for analysis.

scholarly journals Extraction of sugarcane bagasse arabinoxylan, integrated with enzymatic production of xylo-oligosaccharides and separation of cellulose

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Leila Khaleghipour ◽  
Javier A. Linares-Pastén ◽  
Hamid Rashedi ◽  
Seyed Omid Ranaei Siadat ◽  
Andrius Jasilionis ◽  
...  
Keyword(s):  
Sugarcane Bagasse ◽  
Sugar Content ◽  
Value Added ◽  
Apparent Molecular Weight ◽  
Bacillus Halodurans ◽  
Glycoside Hydrolase Family ◽  
High Concentration ◽  
Enzymatic Production ◽  
Successful Separation ◽  
Ft Ir

AbstractSugarcane processing roughly generates 54 million tonnes sugarcane bagasse (SCB)/year, making SCB an important material for upgrading to value-added molecules. In this study, an integrated scheme was developed for separating xylan, lignin and cellulose, followed by production of xylo-oligosaccharides (XOS) from SCB. Xylan extraction conditions were screened in: (1) single extractions in NaOH (0.25, 0.5, or 1 M), 121 °C (1 bar), 30 and 60 min; (2) 3 × repeated extraction cycles in NaOH (1 or 2 M), 121 °C (1 bar), 30 and 60 min or (3) pressurized liquid extractions (PLE), 100 bar, at low alkalinity (0–0.1 M NaOH) in the time and temperature range 10–30 min and 50–150 °C. Higher concentration of alkali (2 M NaOH) increased the xylan yield and resulted in higher apparent molecular weight of the xylan polymer (212 kDa using 1 and 2 M NaOH, vs 47 kDa using 0.5 M NaOH), but decreased the substituent sugar content. Repeated extraction at 2 M NaOH, 121 °C, 60 min solubilized both xylan (85.6% of the SCB xylan), and lignin (84.1% of the lignin), and left cellulose of high purity (95.8%) in the residuals. Solubilized xylan was separated from lignin by precipitation, and a polymer with β-1,4-linked xylose backbone substituted by arabinose and glucuronic acids was confirmed by FT-IR and monosaccharide analysis. XOS yield in subsequent hydrolysis by endo-xylanases (from glycoside hydrolase family 10 or 11) was dependent on extraction conditions, and was highest using xylan extracted by 0.5 M NaOH, (42.3%, using Xyn10A from Bacillus halodurans), with xylobiose and xylotriose as main products. The present study shows successful separation of SCB xylan, lignin, and cellulose. High concentration of alkali, resulted in xylan with lower degree of substitution (especially reduced arabinosylation), while high pressure (using PLE), released more lignin than xylan. Enzymatic hydrolysis was more efficient using xylan extracted at lower alkaline strength and less efficient using xylan obtained by PLE and 2 M NaOH, which may be a consequence of polymer aggregation, via remaining lignin interactions.

scholarly journals Near quantitative synthesis of urea macrocycles enabled by bulky N-substituent

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yingfeng Yang ◽  
Hanze Ying ◽  
Zhixia Li ◽  
Jiang Wang ◽  
Yingying Chen ◽  
...  
Keyword(s):  
High Efficiency ◽  
Molecular Structures ◽  
High Yield ◽  
Kinetic Control ◽  
High Concentration ◽  
Weak Association ◽  
Quantitative Synthesis ◽  
Thermodynamic Stabilization ◽  
Discrete Structures ◽  
Very High

AbstractMacrocycles are unique molecular structures extensively used in the design of catalysts, therapeutics and supramolecular assemblies. Among all reactions reported to date, systems that can produce macrocycles in high yield under high reaction concentrations are rare. Here we report the use of dynamic hindered urea bond (HUB) for the construction of urea macrocycles with very high efficiency. Mixing of equal molar diisocyanate and hindered diamine leads to formation of macrocycles with discrete structures in nearly quantitative yields under high concentration of reactants. The bulky N-tert-butyl plays key roles to facilitate the formation of macrocycles, providing not only the kinetic control due to the formation of the cyclization-promoting cis C = O/tert-butyl conformation, but also possibly the thermodynamic stabilization of macrocycles with weak association interactions. The bulky N-tert-butyl can be readily removed by acid to eliminate the dynamicity of HUB and stabilize the macrocycle structures.

Graduates giving back – a mentoring program for MBA students

2015 ◽  
Vol 4 (3) ◽  
pp. 200-212 ◽  
Author(s):  
Ann Darwin
Keyword(s):  
Higher Education ◽  
South Australia ◽  
Value Added ◽  
Master Of Business Administration ◽  
Mentoring Program ◽  
Education Students ◽  
Content Type ◽  
Mba Students ◽  
A Value ◽  
The University

Purpose – The purpose of this paper is to discuss the challenges and obstacles encountered in the implementation of a mentoring program for Master of Business Administration (MBA) students at the University of South Australia (UniSA) Business School. The paper starts with an exploration into the need for a mentoring program, the trial and subsequent four years of implementation. The paper also explores the network model of mentoring and the reasons why this, rather than a more traditional model, was chosen for the program’s implementation. Design/methodology/approach – This exploratory case study uses data from over 600 students and their alumni mentors over a five-year period to evaluate and improve the program as well as cultivating a critical community of adult learners. Findings – Feedback from students indicates that the mentoring program is regarded by most as a value-added feature of their early learning as it offers support, if and when it is required, from those who have been there before. Research limitations/implications – Results are limited to one institution. However, as research into mentoring for higher education students is thin on the ground, this study contributes to our understanding of the positive impacts of mentoring on student success. Practical implications – This paper emphasizes the importance of business leaders giving back to their alma mater through mentoring current MBA students. It shows how mentoring can support learning and management development. Originality/value – This is an original study which explores ways to increase the learning of higher education students for positive social outcomes.

scholarly journals Overcoming the capital investment hurdle in worker-controlled firms

2019 ◽  
Vol 2 (2) ◽  
pp. 133-150
Author(s):  
Guy Major ◽  
Jonathan Preminger
Keyword(s):  
Capital Investment ◽  
Value Added ◽  
Employee Ownership ◽  
Workplace Democracy ◽  
Equity Investment ◽  
Content Type ◽  
Academic Literature ◽  
Worker Ownership ◽  
Significant Step ◽  
Average Worker

Purpose Both the academic literature and practitioners have long noted the need for an equity investment mechanism for worker-controlled firms that alleviates investor anxieties without undermining internal workplace democracy. The purpose of this paper is to outline one such possible mechanism. Design/methodology/approach The proposal locks together the interests of workers and external investors, via non-voting shares with dividends set by a pre-agreed value-added sharing formula. Each worker is paid a base wage, with the average across the firm being a pre-defined multiple of the national minimum wage. Any additional surplus is split into a number of equal “slices”, with each share receiving one slice as its dividend, and the average worker receiving a pre-agreed number of slices as a bonus. Findings Workers have an incentive to maximise their own incomes, and in so doing, will also automatically maximise the dividends received by investors, obviating the need for the shares to have normal voting rights. Working on this principle of aligned interests, the authors also discuss reinvestment, worker ownership of non-voting shares and possibilities for a secondary share market. The authors show how this proposal will be a significant step in aligning the interests of investors with owner-workers in a democratic, negotiated way that shares both risk and returns, thus making worker-controlled firms more attractive to equity investment. Originality/value In light of the recognised problem of underinvestment in worker-controlled firms and the risk of their degeneration, this paper will interest both academics and practitioners in employee ownership, co-operatives and various forms of workplace democracy.

The impact of intellectual capital on firm performance: a study of Indian firms listed in COSPI

2018 ◽  
Vol 19 (5) ◽  
pp. 935-964 ◽  
Author(s):  
Neha Smriti ◽  
Niladri Das
Keyword(s):  
Firm Performance ◽  
Intellectual Capital ◽  
Value Creation ◽  
Generalized Method Of Moments ◽  
Value Added ◽  
Secondary Data ◽  
Share Price ◽  
Content Type ◽  
Listed Firms ◽  
The Impact

Purpose The purpose of this paper is to examine the effect of intellectual capital (IC) on financial performance (FP) for Indian companies listed on the Centre for Monitoring Indian Economy Overall Share Price Index (COSPI). Design/methodology/approach Hypotheses were developed according to theories and literature review. Secondary data were collected from Indian companies listed on the COSPI between 2001 and 2016, and the value-added intellectual coefficient (VAIC) of Pulic (2000) was used to measure IC and its components. A dynamic system generalized method of moments (SGMM) estimator was employed to identify the variables that significantly contribute to firm performance. Findings Indian listed firms appear to be performing well and efficiently utilizing their IC. Overall, human capital had a major impact on firm productivity during the study period. Furthermore, the empirical analysis showed that structural capital efficiency and capital employed efficiency were equally important contributors to firm’s sales growth and market value. The growing importance of the contribution of IC to value creation was consistently reflected in the FP of these Indian companies. Practical implications This study has robust theoretical grounds and employs a validated methodology. The present study extends knowledge of IC among academicians and managers and highlights its contribution to value creation. The findings may help stakeholders and policymakers in developing countries properly reallocate intellectual resources. Originality/value This study is the first study to evaluate IC and its relationship with traditional measures of firm performance among Indian listed firms using dynamic SGMM and VAIC models.

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