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1.
Bioenergy Res ; : 1-17, 2022 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-35350609

RESUMO

Bio-based fuels and chemicals through the biorefinery approach has gained significant interest as an alternative platform for the petroleum-derived processes as these biobased processes are noticed to have positive environmental and societal impacts. Decades of research was involved in understanding the diversity of microorganisms in different habitats that could synthesize various secondary metabolites that have functional potential as fuels, chemicals, nutraceuticals, food ingredients, and many more. Later, due to the substrate-related process economics, the diverse low-value, high-carbon feedstocks like lignocellulosic biomass, industrial byproducts, and waste streams were investigated to have greater potential. Among them, municipal solid wastes can be used as the source of substrates for the production of commercially viable gaseous and liquid fuels, as well as short-chain fattyacids and carboxylic acids. In this work, technologies and processes demanding the production of value-added products were explained in detail to understand and inculcate the value of municipal solid wastes and the economy, and it can provide to the biorefinery aspect.

2.
Int J Food Microbiol ; 368: 109610, 2022 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-35278799

RESUMO

Oligosaccharides are the sugars made up of 3-10 saccharides units and one of the classes of prebiotics obtained from various biowastes. These biowastes could include rice straw, husk, spent coffee grounds, sugarcane bagasse, spent tea leaves, fruits and vegetables peel, corn stalk, corn stover, deoiled meals and brewer's spent grains etc., which can be used as a resource for oligosaccharides production. This review aims to provide a comprehensive overview of the suitability of different biowaste resources for oligosaccharide production followed by critical analysis of the recent updates and production methods. The review also discusses the tremendous prebiotic potential of oligosaccharides in food applications with prospects for further advancements in the field.


Assuntos
Prebióticos , Saccharum , Celulose , Oligossacarídeos , Prebióticos/análise , Tecnologia
3.
Environ Res ; 207: 112202, 2022 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-34655607

RESUMO

Nowadays, nanoparticles (NPs) and nanomaterials (NMs) are used extensively in various streams such as medical science, solar energy, drug delivery, water treatment, and detection of persistent pollutants. Intensive synthesis of NPs/NMs carried out via physico-chemical technologies is deteriorating the environment globally. Therefore, an urgent need to adopt cost-effective and green technologies to synthesize NPs/NMs by recycling of secondary waste resources is highly required. Environmental wastes such as metallurgical slag, electronics (e-waste), and acid mine drainage (AMD) are rich sources of metals to produce NPs. This concept can remediate the environment on the one hand and the other hand, it can provide a future roadmap for economic benefits at industrial scale operations. The waste-derived NPs will reduce the industrial consumption of limited primary resources. In this review article, green emerging technologies involving lignocellulosic waste to synthesize the NPs from the waste streams and the role of potential microorganisms such as microalgae, fungi, yeast, bacteria for the synthesis of NPs have been discussed. A critical insight is also given on use of recycling technologies and the incorporation of NMs in the membrane bioreactors (MBRs) to improve membrane functioning and process performance. Finally, this study aims to mitigate various persisting scientific and technological challenges for the safe disposal and recycling of organic and inorganic waste for future use in the circular economy.


Assuntos
Nanopartículas , Nanoestruturas , Reatores Biológicos , Metalurgia , Reciclagem
4.
Bioresour Technol ; 346: 126590, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34953996

RESUMO

Lignocellulosic wastes have the ability to be transformed into oligosaccharides and other value-added products. The synthesis of oligosaccharides from renewable sources bestow to growing bioeconomies. Oligosaccharides are synthesized chemically or biologically from agricultural residues. These oligosaccharides are functional food supplements that have a positive impact on humans and livestock. Non-digestible oligosaccharides, refered as prebiotics are beneficial for the colonic microbiota inhabiting the f the digestive system. These microbiota plays a crucial role in stimulating the host immune system and other physiological responses. The commonly known prebiotics, galactooligosaccharides (GOS), xylooligosaccharides (XOS), fructooligosaccharides (FOS), mannanooligosaccharides (MOS), and isomaltooligosaccharides (IOS) are synthesized either through enzymatic or whole cell-mediated approaches using natural or agricultural waste substrates. This review focusses on recent advancements in biological processes, for the synthesis of oligosaccharides using renewable resources (lignocellulosic substrates) for sustainable circular bioeconomy. The work also addresses the limitations associated with the processes and commercialization of the products.


Assuntos
Microbiota , Oligossacarídeos , Suplementos Nutricionais , Humanos , Prebióticos
5.
Sci Total Environ ; 806(Pt 1): 150312, 2022 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-34844320

RESUMO

The single bioprocess approach has certain limitations in terms of process efficiency, product synthesis, and effective resource utilization. Integrated or combined bioprocessing maximizes resource recovery and creates a novel platform to establish sustainable biorefineries. Anaerobic fermentation (AF) is a well-established process for the transformation of organic waste into biogas; conversely, biogas CO2 separation is a challenging and expensive process. Biological fixation of CO2 for succinic acid (SA) mitigates CO2 separation issues and produces commercially important renewable chemicals. Additionally, utilizing digestate rich in volatile fatty acid (VFA) to produce medium-chain fatty acids (MCFAs) creates a novel integrated platform by utilizing residual organic metabolites. The present review encapsulates the advantages and limitations of AF along with biogas CO2 fixation for SA and digestate rich in VFA utilization for MCFA in a closed-loop approach. Biomethane and biohydrogen processes CO2 utilization for SA production is cohesively deliberated along with the role of biohydrogen as an alternative reducing agent to augment SA yields. Similarly, MCFA production using VFA as a substrate and functional role of electron donors namely ethanol, lactate, and hydrogen are comprehensively discussed. A road map to establish the fermentative biorefinery approach in the framework of AF integrated sustainable bioprocess development is deliberated along with limitations and factors influencing for techno-economic analysis. The discussed integrated approach significantly contributes to promote the circular bioeconomy by establishing carbon-neutral processes in accord with sustainable development goals.


Assuntos
Biocombustíveis , Hidrogênio , Anaerobiose , Ácidos Graxos Voláteis , Fermentação , Hidrogênio/análise
6.
Bioresour Technol ; 344(Pt B): 126224, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34751156

RESUMO

Succinic acid (SA) is a top platform chemical obtainable from biomass. The current study evaluated the potential of Actinobacillus succinogenes for SA production using xylose-rich hemicellulosic fractions of two important lignocellulosic feedstocks, olive pits (OP) and sugarcane bagasse (SCB) and the results were compared with pure xylose. Initial experiments were conducted in shake flask followed by batch and fed-batch cultivation in bioreactor. Further separation of SA from the fermented broth was carried out by adapting direct crystallisation method. During fed-batch culture, maximum SA titers of 36.7, 33.6, and 28.7 g/L was achieved on pure xylose, OP and SCB hydrolysates, respectively, with same conversion yield of 0.27 g/g. The recovery yield of SA accumulated on pure xylose, OP and SCB hydrolysates was 79.1, 76.5, and 75.2%, respectively. The results obtained are of substantial value and pave the way for development of sustainable SA biomanufacturing in an integrated biorefinery.


Assuntos
Actinobacillus , Ácido Succínico , Fermentação , Xilose
7.
Sustain Energy Fuels ; 5(19): 4842-4849, 2021 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-34604539

RESUMO

Food waste is a global problem, causing significant environmental harm and resulting in substantial economic losses globally. Bread is the commonly wasted food item in the developed world and presents a severe problem for the majority of European nations. It is the second most wasted food item in the UK after potatoes, with an equivalent of 20 million slices of bread thrown away daily. Bread is a starchy material and a rich and clean source of easily extractable fermentable sugars - this is in direct contrast to lignocellulosic feedstocks where harsh physical, chemical and/or enzymatic pretreatment processes are required for release of fermentable sugars. Furthermore, these necessary lignocellulosic pretreatment methods often produce sugars contaminated with fermentation inhibitors. Therefore, bread waste presents a clear opportunity as a potential carbon source for novel commercial processes and, to this end, several alternative routes have been developed to utilize bread waste. Possibilities for direct recycling of bread waste within the food industry are limited due to the relatively short material lifetime, stringent process and hygiene requirements. Anaerobic digestion (AD) and incineration are commonly employed methods for the valorisation of bread waste, generating limited amounts of green energy but with little other environmental or economic benefits. Most food wastes and by-products in the UK including bakery waste are treated through AD processes that fail to harness the full potential of the these wastes. This short communication reviews the challenges of handling bread waste, with a focus on a specific UK scenario. The review will consider how bread waste is generated across the supply chain, current practices to deal with the waste and logistics challenges in waste collection. The presence of clean and high-quality fermentable sugars, proteins and other nutrients in bread make it an ideal substrate for generating chemicals, fuels, bioplastics, pharmaceuticals and other renewable products through microbial fermentations. We suggest potential applications for recycling bread waste into its chemical building blocks through a fermentative route where a circular biorefining approach could maximize resource recovery and environmental savings and eliminate waste to as close to zero as possible.

8.
Bioresour Technol ; 342: 126005, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34592613

RESUMO

Hemicellulosic sugars, the overlooked fraction of lignocellulosic residues can serve as potential and cost-effective raw material that can be exploited for xylitol production. Xylitol is a top platform chemical with applications in food and pharmaceutical industries. Sugarcane bagasse (SCB) and olive pits (OP) are the major waste streams from sugar and olive oil industries, respectively. The current study evaluated the potential of Pichia fermentans for manufacturing of xylitol from SCB and OP hydrolysates through co-fermentation strategy. The highest xylitol accumulation was noticed with a glucose and xylose ratio of 1:10 followed by feeding with xylose alone. The fed-batch cultivation using pure xylose, SCB, and OP hydrolysates, resulted in xylitol accumulation of 102.5, 86.6 and 71.9 g/L with conversion yield of 0.78, 0.75 and 0.74 g/g, respectively. The non-pathogenic behaviour and ability to accumulate high xylitol levels from agro-industrial residues demonstrates the potential of P. fermentans as microbial cell factory.


Assuntos
Olea , Saccharum , Celulose , Fermentação , Hidrólise , Pichia , Xilitol , Xilose
9.
Bioresour Technol ; 337: 125463, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34320743

RESUMO

Downstream processing of chemicals obtained from fermentative route is challenging and cost-determining factor of any bioprocess. 2,3-Butanediol (BDO) is a promising chemical building block with myriad applications in the polymer, food, pharmaceuticals, and fuel sector. The current study focuses on the recovery and purification of BDO produced (68.2 g/L) from detoxified xylose-rich sugarcane bagasse hydrolysate by a mutant strain of Enterobacter ludwigii. Studies involving screening and optimization of aqueous-two phase system (ATPS) revealed that 30% w/v (NH4)2SO4 addition to clarified fermented broth facilitated BDO extraction in isopropanol (0.5 v/v), with maximum recovery and partition coefficient being 97.9 ± 4.6% and 45.5 ± 3.5, respectively. The optimized protocol was repeated with unfiltered broth containing 68.2 g/L BDO, cell biomass, and unspent protein, which led to the partitioning of 66.7 g/L BDO, 2.0 g/L xylose and 9.0 g/L acetic acid into organic phase with similar BDO recovery (97%) and partition coefficient (45).


Assuntos
Saccharum , Xilose , Butileno Glicóis , Celulose , Enterobacter , Fermentação
10.
J Environ Manage ; 296: 113231, 2021 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-34252850

RESUMO

Heavy metals frequently occur as silent poisons present in our daily diet, the environment we live and the products we use, leaving us victims to various associated drastic health and ecological bad effects even in meagre quantities. The prevalence of heavy metals can be traced from children's toys, electronic goods, industrial effluents, pesticide preparation, and even in drinking water in some instances; necessitating methods to remediate them. The current review discusses the various physicochemical and biological methods employed to tackle the problem of heavy metal pollution. Apart from the conventional methods following the principles of adsorption, precipitation, coagulation, and various separation techniques, the advancements made in the directions of biological heavy metal detoxification using microbes, plants, algae have been critically analyzed to identify the specific utility of different agents for specific heavy metal removal. The review paper is a nutshell of different heavy metal remediation strategies, their merits, demerits, and modifications done to alleviate process of heavy metal pollution.


Assuntos
Metais Pesados , Adsorção , Biodegradação Ambiental , Criança , Humanos , Metais Pesados/toxicidade , Plantas
11.
Sci Total Environ ; 794: 148751, 2021 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-34218145

RESUMO

Mono alkyl fatty acid ester or methyl ethyl esters (biodiesel) are the promising alternative for fossil fuel or petroleum derived diesel with similar properties and could reduce the carbon foot print and the greenhouse gas emissions. Biodiesel can be produced from renewable and sustainable feedstocks like plant derived oils, and it is biodegradable and non-toxic to the ecosystem. The process for the biodiesel production is either through traditional chemical catalysts (Acid or Alkali Transesterification) or enzyme mediated transesterification, but as enzymes are natural catalysts with environmentally friendly working conditions, the process with enzymes are proposed to overcome the drawbacks of chemical synthesis. At present 95% of the biodiesel production is contributed by edible oils worldwide whereas recycled oils and animal fats contribute 10% and 6% respectively. Although every process has its own limitations, the enzyme efficiency, resistance to alcohols, and recovery rate are the crucial factors to be addressed. Without any benefit of doubt, production of biodiesel using renewable feedstocks and enzymes as the catalysts could be recommended for the commercial purpose, but further research on improving the efficiency could be an advantage.


Assuntos
Biocombustíveis , Petróleo , Animais , Ecossistema , Esterificação , Ésteres , Óleos Vegetais
12.
Bioresour Technol ; 337: 125426, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34174767

RESUMO

In the present study, we have explored the potential of newly isolated Aspergillus terreus BD strain, which can accumulate itaconic acid (IA) at higher temperature. The shake flask cultivation of thermotolerant strain with medium optimized using Box-Behnken Design at 45 °C resulted in IA accumulation of 28.9 g/L with yield of 0.27 g/g. The enzymatic saccharification of the synthetic food waste (SFW) consisting of potatoes, rice & noodles were optimized using Taguchi method of orthogonal array to maximize the release of fermentable sugar. The maximum glucose release of 0.60 g/g was achieved with 10% biomass loading, 5% enzyme concentration, pH 5.5 and temperature 60 0C. The sugars obtained from SFW was integrated with IA production and maximum IA titer achieved with SFW hydrolysate during bioreactor cultivation was 41.1 g/L with conversion yield of 0.27 g/g while with pure glucose IA titer and yield were 44.7 g/L and 0.30 g/g, respectively.


Assuntos
Alimentos , Eliminação de Resíduos , Aspergillus , Fermentação , Succinatos
13.
Sustain Energy Fuels ; 6(1): 29-65, 2021 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-35028420

RESUMO

Biologists and engineers are making tremendous efforts in contributing to a sustainable and green society. To that end, there is growing interest in waste management and valorisation. Lignocellulosic biomass (LCB) is the most abundant material on the earth and an inevitable waste predominantly originating from agricultural residues, forest biomass and municipal solid waste streams. LCB serves as the renewable feedstock for clean and sustainable processes and products with low carbon emission. Cellulose and hemicellulose constitute the polymeric structure of LCB, which on depolymerisation liberates oligomeric or monomeric glucose and xylose, respectively. The preferential utilization of glucose and/or absence of the xylose metabolic pathway in microbial systems cause xylose valorization to be alienated and abandoned, a major bottleneck in the commercial viability of LCB-based biorefineries. Xylose is the second most abundant sugar in LCB, but a non-conventional industrial substrate unlike glucose. The current review seeks to summarize the recent developments in the biological conversion of xylose into a myriad of sustainable products and associated challenges. The review discusses the microbiology, genetics, and biochemistry of xylose metabolism with hurdles requiring debottlenecking for efficient xylose assimilation. It further describes the product formation by microbial cell factories which can assimilate xylose naturally and rewiring of metabolic networks to ameliorate xylose-based bioproduction in native as well as non-native strains. The review also includes a case study that provides an argument on a suitable pathway for optimal cell growth and succinic acid (SA) production from xylose through elementary flux mode analysis. Finally, a product portfolio from xylose bioconversion has been evaluated along with significant developments made through enzyme, metabolic and process engineering approaches, to maximize the product titers and yield, eventually empowering LCB-based biorefineries. Towards the end, the review is wrapped up with current challenges, concluding remarks, and prospects with an argument for intense future research into xylose-based biorefineries.

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