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•Inhibitors produced by pretreatment of lignocellulosic biomass inhibit microbial and enzymic processes.•The inhibitors produced during pretreatment process by different components ...are steadily reviewed.•The physical, chemical and biological methods used for detoxification are discussed.•The challenges and possibilities of inhibitor removal are identified.
The main objective of biomass pretreatment is to separate biomass components and provide easier access with ultimate aim for lignin removal, hemicellulose protection and cellulose crystallinity reduction. Effective bioconversion with least inhibitory compound production would play a considerable role in economic practicability of the process in order to achieve economic sustainability. In this regard, detoxification is an important condition to make biomass hydrolysate acquiescent to bioconversion; also, understanding of inhibitors effect on growth and fermentation are necessary requirements for system detoxification. A number of physical, chemical and biological methods like feedstock selection, membrane selection, neutralization, use of activated charcoal etc have been recommended and developed for removal or minimizing the inhibitory compounds effect. This work reviews various inhibitory compounds produced during pretreatment methods and their removal by various processes.
Outlines the diverse environmental sustainability benefits of using NBMs. Notable, these NBms are crucial in carbon sequestration; they vigorously captivate carbon dioxide, weakening harmful ...emissions and thus, playing an instrumental role in opposing climate change.
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•Covers the synthetic and natural nanomaterials for enhancing the performance of building materials (BMs).•Applications of NCs in cement, tiles, engineered wood, and insulating materials used in construction industry.•NMs in BMs for reducing carbon footprint, enhanced energy efficiency, toxicity concerns, and LCA of NBMs.•Regulatory barriers to the adoption of sustainable nanoengineered building materials (NBMs).•AI applications in building energy saving.
Nanomaterials (NMs) use in building materials (BMs) has still not been widely explored, despite its boundless potential in developing novel, smart, eco-efficient and high performance BMs based on the addition of nanoparticles (NPs). NPs are used as fillers in nanocomposites because they have many unique and useful properties. Recently, NPs have been used in the manufacture of BMs to improve their performances, reduce associated carbon footprint, and reduce energy consumption. Nanoengineered building materials (NBMs) have many positive impacts on the construction industry. NBMs derived from renewable sources are a promising alternative, significantly reducing the greenhouse effect and enhancing energy efficiency. The BMs can be designed with desired properties to obtain better performance sustainability and more energy efficiency. In addition, the use of NBMs decreases the construction time, and improves the environmental quality of the building and the laborers required for constructing the buildings. NBMs have augmented surface area, more surface functionalities, and larger pore volume. These NBMs with functionalized chemical groups have countless potential to arrest greenhouse gases. Given this, it has been observed that the use of NBMs in the construction industry can reduce energy consumption and carbon dioxide emission by 25%, reduce water absorption, enhance acoustic absorption, and augment mechanical properties. In this review, we will try to cover the latest developments in the use of synthetic and natural NMs which can help in constructing more energy efficient, sustainable BMs with less carbon footprint. In addition, we have also covered the environmental benefits, implications, and toxicity concerns of NBMs.
Stevia rebaudiana, a perennial herb from the Asteraceae family, is known to the scientific world for its sweetness and steviol glycosides (SGs). SGs are the secondary metabolites responsible for the ...sweetness of Stevia. They are synthesized by SG biosynthesis pathway operating in the leaves. Most of the genes encoding the enzymes of this pathway have been cloned and characterized from Stevia. Out of various SGs, stevioside and rebaudioside A are the major metabolites. SGs including stevioside have also been synthesized by enzymes and microbial agents. These are non-mutagenic, non-toxic, antimicrobial, and do not show any remarkable side-effects upon consumption. Stevioside has many medical applications and its role against diabetes is most important. SGs have made Stevia an important part of the medicinal world as well as the food and beverage industry. This article presents an overview on Stevia and the importance of SGs.
The human population is increasing at an alarming rate, whereas at the same time agricultural productivity is decreasing due to the effect of various environmental problems. In particular, cold ...stress is a serious threat to the sustainability of crop yields. Indeed, cold stress can lead to major crop losses. Various phenotypic symptoms in response to cold stress include poor germination, stunted seedlings, yellowing of leaves (chlorosis), reduced leaf expansion and wilting, and may lead to death of tissue (necrosis). Cold stress also severely hampers the reproductive development of plants. The major negative effect of cold stress is that it induces severe membrane damage. This damage is largely due to the acute dehydration associated with freezing during cold stress. Cold stress is perceived by the receptor at the cell membrane. Then a signal is transduced to switch on the cold-responsive genes and transcription factors for mediating stress tolerance. Understanding the mechanism of cold stress tolerance and genes involved in the cold stress signaling network is important for crop improvement. Here, I review cold stress tolerance mechanisms in plants. The major points discussed are the following: (1) physiological effects of cold stress, (2) sensing of cold temperatures and signal transduction, and (3) the role of various cold-responsive genes and transcription factors in the mechanism of cold stress tolerance.
Green synthesis of metallic nanoparticles (NPs) has been extensively carried out by using plant extracts (PEs) which have property of stabilizers/emulsifiers. To our knowledge, there is no ...comprehensive study on applying a green approach using PEs for fabrication of biodegradable PLA NPs. Conventional methods rely on molecules like polyvinyl alcohol, polyethylene glycol, D-alpha-tocopheryl poly(ethylene glycol 1000) succinate as stabilizers/emulsifiers for the synthesis of such biodegradable NPs which are known to be toxic. So, there is urgent need to look for stabilizers which are biogenic and non-toxic. The present study investigated use of PEs as stabilizers/emulsifiers for the fabrication of stable PLA NPs. Synthesized PLA NPs through this green process were explored for controlled release of the well known antioxidant molecule quercetin.
Stable PLA NPs were synthesized using leaf extracts of medicinally important plants like Syzygium cumini (1), Bauhinia variegata (2), Cedrus deodara (3), Lonicera japonica (4) and Eleaocarpus sphaericus (5). Small and uniformly distributed NPs in the size range 70±30 nm to 143±36 nm were formed with these PEs. To explore such NPs for drugs/ small molecules delivery, we have successfully encapsulated quercetin a lipophilic molecule on a most uniformly distributed PLA-4 NPs synthesized using Lonicera japonica leaf extract. Quercetin loaded PLA-4 NPs were observed for slow and sustained release of quercetin molecule.
This green approach based on PEs mediated synthesis of stable PLA NPs pave the way for encapsulating drug/small molecules, nutraceuticals and other bioactive ingredients for safer cellular uptake, biodistribution and targeted delivery. Hence, such PEs synthesized PLA NPs would be useful to enhance the therapeutic efficacy of encapsulated small molecules/drugs. Furthermore, different types of plants can be explored for the synthesis of PLA as well as other polymeric NPs of smaller size.
Nanobiotechnology deals with the synthesis of nanostructures using living organisms. Among the use of living organisms for nanoparticle synthesis, plants have found application particularly in metal ...nanoparticle synthesis. Use of plants for synthesis of nanoparticles could be advantageous over other environmentally benign biological processes as this eliminates the elaborate process of maintaining cell cultures. Biosynthetic processes for nanoparticles would be more useful if nanoparticles were produced extracellularly using plants or their extracts and in a controlled manner according to their size, dispersity and shape. Plant use can also be suitably scaled up for large-scale synthesis of nanoparticles. In view of this, we have reviewed here the use of plants or their extracts in the synthesis of silver and gold nanoparticles for various human applications. Copyright
Carbon quantum dots (CQDs) are a class of carbon nanomaterials that have recently gained recognition as current entrants to traditional semiconductor quantum dots. CQDs have the desirable advantages ...of low toxicity, environmental friendliness, low cost, photostability, favorable charge transfer with enhanced electronic conductivity, and comparable easy-synthesis protocols. This review examines the advancements in CQD research and development, with a focus on their synthesis, functionalization, and energy applications. Initially, various synthesis methods are discussed briefly with pros and cons. Herein, first top-down methods including the arc-discharge technique, laser ablation technique, plasma treatment, ultrasound synthesis technique, electrochemical technique, chemical exfoliation, and combustion were discussed briefly. The later section presents bottom-up (microwave synthesis, hydrothermal synthesis, thermal pyrolysis, and metal–organic framework template-assisted approach) and waste-derived CQD synthesis methods. The next section is focused on the energy applications of CQDs including supercapacitors, lithium-ion batteries, photovoltaics, hydrogen evolution reaction and oxygen evolution reaction. Finally, challenges and future perspectives in this exciting and promising area are presented.
•Microbes from urban green spaces may help to shape the human microbiome.•After urban green space exposure, skin and nasal microbial diversity increased.•Skin and nasal microbial composition became ...more similar to environmental sources.•Nasal microbiota are more variable between sites and individuals than skin microbiota.
In industrialized countries, non-communicable diseases have been increasing in prevalence since the middle of the 20th century. While the causal mechanisms remain poorly understood, increased population density, pollution, sedentary behavior, smoking, changes in diet, and limited outdoor exposure have all been proposed as significant contributors. Several hypotheses (e.g. Hygiene, Old Friends, and Biodiversity Hypotheses) also suggest that limited environmental microbial exposures may underpin part of this rise in non-communicable diseases. In response, the Microbiome Rewilding Hypothesis proposes that adequate environmental microbial exposures could be achieved by restoring urban green spaces and could potentially decrease the prevalence of non-communicable diseases. However, the microbial interactions between humans and their surrounding environment and the passaging of microbes between both entities remains poorly understood, especially within an urban context.
Here, we survey human skin (n = 90 swabs) and nasal (n = 90 swabs) microbiota of three subjects that were exposed to air (n = 15), soil (n = 15), and leaves (n = 15) from different urban green space environments in three different cities across different continents (Adelaide, Australia; Bournemouth, United Kingdom; New Delhi, India). Using 16S ribosomal RNA metabarcoding, we examined baseline controls (pre-exposure) of both skin (n = 16) and nasal (n = 16) swabs and tracked microbiota transfer from the environment to the human body after exposure events. Microbial richness and phylogenetic diversity increased after urban green space exposure in skin and nasal samples collected in two of the three locations. The microbial composition of skin samples also became more similar to soil microbiota after exposure, while nasal samples became more similar to air samples. Nasal samples were more variable between sites and individuals than skin samples.
We show that exposure to urban green spaces can increase skin and nasal microbial diversity and alter human microbiota composition. Our study improves our understanding of human-environmental microbial interactions and suggests that increased exposure to diverse outdoor environments may increase the microbial diversity, which could lead to positive health outcomes for non-communicable diseases.
Size distribution, water-soluble inorganic ions (WSII), and organic carbon (OC) and elemental carbon (EC) in size-segregated aerosols were investigated during a year-long sampling in 2010 over New ...Delhi. Among different size fractions of PM
10
, PM
0.95
was the dominant fraction (45%) followed by PM
3–7.2
(20%), PM
7.2–10
(15%), PM
0.95–1.5
(10%), and PM
1.5–3
(10%). All size fractions exceeded the ambient air quality standards of India for PM
2.5
. Annual average mass size distributions of ions were specific to size and ion(s); Ca
2+
, Mg
2+
, K
+
, NO
3
−
, and Cl
−
followed bimodal distribution while SO
4
2−
and NH
4
+
ions showed one mode in PM
0.95
. The concentrations of secondary WSII (NO
3
−
, SO
4
2−
, and NH
4
+
) increased in winters due to closed and moist atmosphere whereas open atmospheric conditions in summers lead to dispersal of pollutants. NH
4
+
and Ca
2+
were dominant neutralization ions but in different size fractions. The summer-time dust transport from upwind region by S SW winds resulted in significantly high concentrations of PM
0.95
and PM
3–7.2
and PM
7.2–10
. This indicted influence of dust generation in Thar Desert and its transport is size selective in nature in downwind direction. The mixing of different sources (geogenic, coal combustions, biomass burning, plastic burning, incinerators, and vehicular emissions sources) for soluble ions in different size fractions was noticed in principle component analysis. Total carbon (TC = EC + OC) constituted 8–31% of the total PM
0.95
mass, and OC dominated over EC. Among EC, char (EC1) dominated over soot (EC2 + EC3). High SOC contribution (82%) to OC and OC/EC ratio of 2.7 suggested possible role of mineral dust and high photochemical activity in SOC production. Mass concentrations of aerosols and WSII and their contributions to each size fraction of PM
10
are governed by nature of sources, emission strength of source(s), and seasonality in meteorological parameters.
Steviol glycoside biosynthesis pathway has emerged as bifurcation from ent-kaurenoic acid, substrate of methyl erythritol phosphate pathway that also leads to gibberellin biosynthesis. However, the ...genetic regulation of steviol glycoside biosynthesis has not been studied. So, in present study RNA interference (RNAi) based Agrobacterium mediated transient gene silencing (AMTS) approach was followed. SrKA13H and three SrUGTs (SrUGT85C2, SrUGT74G1 and SrUGT76G1) genes encoding ent-kaurenoic acid-13 hydroxylase and three UDP glycosyltransferases of steviol glycoside biosynthesis pathway were silenced in Stevia rebaudiana to understand its molecular mechanism and association with gibberellins.
RNAi mediated AMTS of SrKA13H and three SrUGTs has significantly reduced the expression of targeted endogenous genes as well as total steviol glycoside accumulation. While gibberellins (GA3) content was significantly enhanced on AMTS of SrUGT85C2 and SrKA13H. Silencing of SrKA13H and SrUGT85C2 was found to block the metabolite flux of steviol glycoside pathway and shifted it towards GA3 biosynthesis. Further, molecular docking of three SrUGT proteins has documented highest affinity of SrUGT76G1 for the substrates of alternate pathways synthesizing steviol glycosides. This could be a plausible reason for maximum reduction in steviol glycoside content on silencing of SrUGT76G1 than other genes.
SrKA13H and SrUGT85C2 were identified as regulatory genes influencing carbon flux between steviol glycoside and gibberellin biosynthesis. This study has also documented the existence of alternate steviol glycoside biosynthesis route.
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