Optimization of Xylose Reductase production from Citrobacter sp.

2021 ◽  
Vol 16 (8) ◽  
pp. 90-97
Author(s):  
Rashmi Niranjan ◽  
Vishal Ahuja ◽  
Arvind Kumar Bhatt
Keyword(s):  
Large Scale ◽  
Bacterial Isolate ◽  
Healthy Lifestyle ◽  
Xylose Reductase ◽  
Value Added ◽  
Cost Effective ◽  
Xylitol Production ◽  
Straight Chain ◽  
Bone Demineralization ◽  
Value Added Products

Xylitol is a poly-hydroxy straight-chain five-carbon alcohol that can replace sugar in daily uses without any side effects. Lowered risk of dental carries and bone demineralization further support its involvement in a healthy lifestyle. In addition, its role in the synthesis of various commercial products like glycol, ethanol, and resins etc. increases its market value and makes it one of the most valuable bio-products. Microbial fermentation is a cost-effective and eco-friendly method for xylitol production from agricultural residues as available xylose is reduced to xylitol by Xylose reductase (XR) using an equivalent amount of NADPH as a mediator for electron transfer. Previous literature emphasized the use of fungi and yeast for xylitol production rather than bacteria. In contrast to available reports, the potential of the bacterial isolate was evaluated for xylitol production. The effect of process parameters was observed on xylitol yield in terms of XR activity. Out of sixty-eight bacterial isolates obtained, XYLBV-05 was selected for XR production after screening and was identified as Citrobacter sp. based on morphological, microscopic, and biochemical characteristics. Parametric analysis increased the XR production by 4.12 folds (36.61 U/ml). Preliminary results also proved its efficiency in conversion of biomass hydrolysate to xylitol at lab scale but further efforts are needed for xylitol production using agro-industrial lignocellulosic biomass at a large scale which will not only aid in the generation of revenue as a result of value-added products but will also help in environment conservation.

scholarly journals Multi-Country Scale Assessment of Available Energy Recovery Potential Using Micro-Hydropower in Drinking, Pressurised Irrigation and Wastewater Networks, Covering Part of the EU

Water ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 899
Author(s):  
Djordje Mitrovic ◽  
Miguel Crespo Chacón ◽  
Aida Mérida García ◽  
Jorge García Morillo ◽  
Juan Antonio Rodríguez Diaz ◽  
...  
Keyword(s):  
Drinking Water ◽  
Northern Ireland ◽  
Energy Recovery ◽  
Large Scale ◽  
Significant Proportion ◽  
Value Added ◽  
Cost Effective ◽  
Net Energy ◽  
Water Networks ◽  
Scale Assessment

Studies have shown micro-hydropower (MHP) opportunities for energy recovery and CO2 reductions in the water sector. This paper conducts a large-scale assessment of this potential using a dataset amassed across six EU countries (Ireland, Northern Ireland, Scotland, Wales, Spain, and Portugal) for the drinking water, irrigation, and wastewater sectors. Extrapolating the collected data, the total annual MHP potential was estimated between 482.3 and 821.6 GWh, depending on the assumptions, divided among Ireland (15.5–32.2 GWh), Scotland (17.8–139.7 GWh), Northern Ireland (5.9–8.2 GWh), Wales (10.2–8.1 GWh), Spain (375.3–539.9 GWh), and Portugal (57.6–93.5 GWh) and distributed across the drinking water (43–67%), irrigation (51–30%), and wastewater (6–3%) sectors. The findings demonstrated reductions in energy consumption in water networks between 1.7 and 13.0%. Forty-five percent of the energy estimated from the analysed sites was associated with just 3% of their number, having a power output capacity >15 kW. This demonstrated that a significant proportion of energy could be exploited at a small number of sites, with a valuable contribution to net energy efficiency gains and CO2 emission reductions. This also demonstrates cost-effective, value-added, multi-country benefits to policy makers, establishing the case to incentivise MHP in water networks to help achieve the desired CO2 emissions reductions targets.

scholarly journals Exploiting xylan as sugar donor for the synthesis of an antiproliferative xyloside using an enzyme cascade

2019 ◽  
Vol 18 (1) ◽  
Author(s):  
Manuel Nieto-Domínguez ◽  
José Alberto Martínez-Fernández ◽  
Beatriz Fernández de Toro ◽  
Juan A. Méndez-Líter ◽  
Francisco Javier Cañada ◽  
...  
Keyword(s):  
Chemical Synthesis ◽  
Biomass Conversion ◽  
Value Added ◽  
Cost Effective ◽  
Raw Material ◽  
Birchwood Xylan ◽  
Enzyme Cascade ◽  
Antiproliferative Agent ◽  
Xylanolytic Enzymes ◽  
Value Added Products

Abstract Background Currently, industrial societies are seeking for green alternatives to conventional chemical synthesis. This demand has merged with the efforts to convert lignocellulosic biomass into value-added products. In this context, xylan, as one of main components of lignocellulose, has emerged as a raw material with high potential for advancing towards a sustainable economy. Results In this study, the recombinant endoxylanase rXynM from the ascomycete Talaromyces amestolkiae has been heterologously expressed in Pichia pastoris and used as one of the catalysts of an enzyme cascade developed to synthesize the antiproliferative 2-(6-hydroxynaphthyl) β-d-xylopyranoside, by transglycosylation of 2,6-dihydroxynaphthalene. The approach combines the use of two fungal xylanolytic enzymes, rXynM and the β-xylosidase rBxTW1 from the same fungus, with the cost-effective substrate xylan. The reaction conditions for the cascade were optimized by a Central Composite Design. Maximal productions of 0.59 and 0.38 g/L were reached using beechwood xylan and birchwood xylan, respectively. For comparison, xylans from other sources were tested in the same reaction, suggesting that a specific optimization is required for each xylan variety. The results obtained using this enzyme cascade and xylan were similar or better to those previously reported for a single catalyst and xylobiose, an expensive sugar donor. Conclusions Beechwood and birchwood xylan, two polysaccharides easily available from biomass, were used in a novel enzyme cascade to synthetize an antiproliferative agent. The approach represents a green alternative to the conventional chemical synthesis of 2-(6-hydroxynaphthyl) β-d-xylopyranoside using a cost-effective substrate. The work highlights the role of xylan as a raw material for producing value-added products and the potential of fungal xylanolytic enzymes in the biomass conversion.

scholarly journals Assessing the Potential of Newly Isolated Pichia Fermentans for Xylitol Production Using Non-Detoxified Xylose Rich Pre-Hydrolysate Derived from Sugarcane Bagasse

2020 ◽  
Author(s):  
Ashish A Prabhu ◽  
Ekkarin Bosakornranut ◽  
Yassin Amraoui ◽  
Deepti Agarwal ◽  
Frederic Coulon ◽  
...  
Keyword(s):  
Sugarcane Bagasse ◽  
Type Strain ◽  
Shake Flask ◽  
Wild Type Strain ◽  
Xylose Reductase ◽  
Value Added ◽  
Xylitol Production ◽  
Wild Type ◽  
Conversion Yield ◽  
Cell Factories

Abstract Background: Integrated management of hemicellulosic fraction and its economical transformation to value-added products is the key driver towards sustainable second-generation biorefineries. In this aspect microbial cell factories are harnessed for sustainable production of biochemicals by valorising C5 and C6 sugars generated from agro-industrial waste. However, most of the strains can effectively consume C6 sugars but lacks pentose metabolism pathway. The effective utilization of both pentose and hexose sugars is key for economical biorefinery. Results: In the current study, the ability of a newly isolated xylose assimilating Pichia fermentans was explored for xylitol production. The wild type strain robustly grew on xylose and produced xylitol with >40% conversion yield. Mutagenesis with ethyl methanesulphonate (EMS) yielded seven mutants. The mutant obtained after 15 min exposure, exhibited best xylose bioconversion efficiency. This mutant under shake flask conditions produced maximum xylitol titre and yield of 34.0 g/L and 0.68 g/g, respectively. oweverHoHHHoHowever, under same conditions, the control wild type strain accumulated 27.0 g/L xylitol with a conversion yield of 0.45 g/g. Improved performance of the mutant was attributed to 34.6% activity enhancement in xylose reductase with simultaneous reduction of xylitol dehydrogenase activity by 22.9%. Later, the culture medium was optimized using statistical design and validated at shake flask and bioreactor level. Bioreactor studies affirmed the competence of mutant in xylitol accumulation. The xylitol titre and yield obtained with pure xylose were 98.9 g/L and 0.67 g/g, respectively while xylitol produced using non-detoxified xylose rich pre-hydrolysate from sugarcane bagasse was 79.0 g/L with an overall yield of 0.54 g/g. Conclusion: This study established the potential of P. fermentans in successfully valorising the hemicellulosic fraction for sustainable xylitol production.

scholarly journals Biotechnological Valorization of Pectinolytics and Their Industrial Applications: A Review

2014 ◽  
Vol 9 (11) ◽  
pp. 1934578X1400901 ◽  
Author(s):  
Muhammad Irshad ◽  
Muhammad Asgher ◽  
Zahid Anwar ◽  
Aftab Ahmad
Keyword(s):  
Large Scale ◽  
Value Added ◽  
Cost Effective ◽  
Industrial Applications ◽  
Green Biotechnology ◽  
A Value ◽  
Physico Chemical ◽  
Target Yield ◽  
High Yields ◽  
Agricultural Materials

In the last several years, in serious consideration of the worldwide economic and environmental issues there has been an increasing research interest in the value of naturally occurring bio-sourced materials. Agro-industrial based biomass comprised of pectin is an inexpensive, renewable, abundant natural resource that could be utilized for large-scale and cost-effective production of natural products i.e., pectinolytics. Pectinolytics are one of the most widely distributed enzymes in bacteria, fungi and plants. From ancient times to date, many methods have been introduced to improve the optimization of pectinolytics to obtain high yields of maximal purity. To expand the range of natural bio-resources the rapidly evolving tools of biotechnology can lower the conversion costs and also enhance target yield of the product of interest. This green biotechnology presents a promising approach to convert most of the agricultural materials into a value-added product with multiple applications. Major advances have already been achieved in recent years in order to obtain high levels of purity with optimal yields. The present review begins with an overview of pectinolytics and their physico-chemical features, and their specific role with classification based on pectic materials. Information is also given on the culture influences and potential sources of pectinolytics, followed by a brief summary of various industrial and biotechnological applications and future considerations.

Vertical-algal-biofilm enhanced raceway pond for cost-effective wastewater treatment and value-added products production

2018 ◽  
Vol 139 ◽  
pp. 144-157 ◽  
Author(s):  
Qi Zhang ◽  
Zhigang Yu ◽  
Liandong Zhu ◽  
Ting Ye ◽  
Jiaolan Zuo ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Value Added ◽  
Cost Effective ◽  
Raceway Pond ◽  
Algal Biofilm ◽  
Value Added Products

A Reanalysis of the Effects of Teacher Replacement Using Value-Added Modeling

2013 ◽  
Vol 115 (12) ◽  
pp. 1-35
Author(s):  
Stuart S. Yeh
Keyword(s):  
Student Achievement ◽  
Large Scale ◽  
Reliability And Validity ◽  
Value Added ◽  
Cost Effective ◽  
Large Numbers ◽  
Cost Effective Approach ◽  
Need To Evaluate ◽  
Value Added Modeling ◽  
Lifetime Earnings

Background In principle, value-added modeling (VAM) might be justified if it can be shown to be a more reliable indicator of teacher quality than existing indicators for existing low-stakes decisions that are already being made, such as the award of small merit bonuses. However, a growing number of researchers now advocate the use of VAM to identify and replace large numbers of low-performing teachers. There is a need to evaluate these proposals because the active termination of large numbers of teachers based on VAM requires a much higher standard of reliability and validity. Furthermore, these proposals must be evaluated to determine if they are cost-effective compared to alternative proposals for raising student achievement. While VAM might be justified as a replacement for existing indicators (for existing decisions regarding merit compensation), it might not meet the higher standard of reliability and validity required for large-scale teacher termination, and it may not be the most cost-effective approach for raising student achievement. If society devotes its resources to approaches that are not cost-effective, the increase in achievement per dollar of resources expended will remain low, inhibiting reduction of the achievement gap. Objective This article reviews literature regarding the reliability and validity of VAM, then focuses on an evaluation of a proposal by Chetty, Friedman, and Rockoff to use VAM to identify and replace the lowest-performing 5% of teachers with average teachers. Chetty et al. estimate that implementation of this proposal would increase the achievement and lifetime earnings of students. The results appear likely to accelerate the adoption of VAM by school districts nationwide. The objective of the current article is to evaluate the Chetty et al. proposal and the strategy of raising student achievement by using VAM to identify and replace low-performing teachers. Method This article analyzes the assumptions of the Chetty et al. study and the assumptions of similar VAM-based proposals to raise student achievement. This analysis establishes a basis for evaluating the Chetty et al. proposal and, in general, a basis for evaluating all VAM-based policies to raise achievement. Conclusion VAM is not reliable or valid, and VAM-based polices are not cost-effective for the purpose of raising student achievement and increasing earnings by terminating large numbers of low-performing teachers.

scholarly journals Sustainable Cost-Effective Microalgae Harvesting Strategies for the Production of Biofuel and Oleochemicals

2020 ◽  
Author(s):  
Suchitra Rakesh ◽  
Jayakumar TharunKumar ◽  
Bhavya Sri ◽  
Karuppaiyan Jothibasu ◽  
Subburamu Karthikeyan
Keyword(s):  
Low Cost ◽  
Biomass Concentration ◽  
Value Added ◽  
Cost Effective ◽  
Future Perspective ◽  
Dissolved Air Flotation ◽  
Capital Costs ◽  
Microalgae Harvesting ◽  
Problematic Area ◽  
Value Added Products

Microalgae have been explored for sustainable production of biofuel and chemicals. Microalgae is promising feed stock for the production of several oleochemicals. It has the ability to utilize a variety of low cost feed stocks, accumulated large quantities of lipids and variety of value added products in their biomass. One of the major obstacles associated with the conversion of algae into value-added products is harvesting. The harvesting of algae is the most problematic area due to its low sedimentation rate, low biomass concentration, and high capital costs. Harvesting of algae is carried out by different physical, chemical, mechanical, biological, and electrolytic methods such as sedimentation, centrifugation, microstraining, dissolved air flotation, electrolytic flotation, chemical flocculation, bioflocculation, autoflocculation, Filtration. This review highlights the various methods of microalgae harvesting with advantages and future perspective of sustainable and cost-effective harvesting of microalgae.

scholarly journals Strategies to Produce Cost-Effective Third-Generation Biofuel From Microalgae

2021 ◽  
Vol 9 ◽  
Author(s):  
Nazifa Rafa ◽  
Shams Forruque Ahmed ◽  
Irfan Anjum Badruddin ◽  
M. Mofijur ◽  
Sarfaraz Kamangar
Keyword(s):  
Large Scale ◽  
Cost Minimization ◽  
Value Added ◽  
Cost Effective ◽  
Global Market ◽  
Production Costs ◽  
Biodiesel Production ◽  
Third Generation ◽  
The Cost ◽  
Generation Biofuel

Third-generation biofuel produced from microalgae is a viable solution to global energy insecurity and climate change. Despite an annual current global algal biomass production of 38 million litres, commercialization confronts significant economic challenges. However, cost minimization strategies, particularly for microalgae cultivation, have largely been excluded from recent studies. Therefore, this review provides essential insights into the technologies and economics of cost minimization strategies for large-scale applications. Cultivation of microalgae through aquafarming, in wastewater, or for biogas upgrading, and co-production of value-added products (VAPs) such as photo-bioreactors, protein, astaxanthin, and exopolysaccharides can drastically reduce biodiesel production costs. For instance, the co-production of photo-bioreactors and astaxanthin can reduce the cost of biodiesel production from $3.90 to $0.54 per litre. Though many technical challenges need to be addressed, the economic analysis reveals that incorporating such cost-effective strategies can make the biorefinery concept feasible and profitable. The cost of producing microalgal biodiesel can be lowered to $0.73kg−1 dry weight when cultivated in wastewater or $0.54L−1 when co-produced with VAPs. Most importantly, access to co-product markets with higher VAPs needs to be encouraged as the global market for microalgae-based VAPs is estimated to rise to $53.43 billion in 2026. Therefore, policies that incentivize research and development, as well as the production and consumption of microalgae-based biodiesel, are important to reduce the large gap in production cost that persists between biodiesel and petroleum diesel.

scholarly journals Utility Potential ofParthenium hysterophorusfor Its Strategic Management

2014 ◽  
Vol 2014 ◽  
pp. 1-16 ◽  
Author(s):  
Anita Saini ◽  
Neeraj K. Aggarwal ◽  
Anuja Sharma ◽  
Manpreet Kaur ◽  
Anita Yadav
Keyword(s):  
Large Scale ◽  
Control Strategies ◽  
Chemical Constituents ◽  
Value Added ◽  
Holistic Approach ◽  
Parthenium Hysterophorus ◽  
Human Beings ◽  
Pharmacological Activities ◽  
Competitive Success ◽  
Value Added Products

Parthenium hysterophorus, one of the world’s most dangerous weeds, is responsible for huge losses to the biodiversity, agriculture, economy, and health of livestock and human beings. High competitive success rate and adaptability of the species enable it to dominate diverse types of habitats. Various weed control strategies are being used globally to reduce its population to manageable levels. But owing to many limitations associated with the conventional methods, management ofPartheniumstill remains a challenge. Recently large scale utilization has been taken up as a holistic approach for the control of weeds.Parthenium hysterophoruscan be managed by exploiting this weed in diverse fields. In agriculture, it can be used either as green manure or after composting. Industrially it can be used for producing various value added products. The weed also exhibits many environmental applications. Chemical constituents ofPartheniumshow extensive range of pharmacological activities suggesting its role as a chemotherapeutic agent. This review briefly discusses the problem ofPartheniumand enlists its possible utilities which can open new avenues for effective management of this violent weed.

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