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Acidophiles are a group of organisms typically found in highly acidic environments such as acid mine drainage. These organisms have several physiological features that enable them to thrive in highly acidic environments (pH ≤3). Considering that both acid mine drainage and solfatara fields exhibit extreme and dynamic ecological conditions for acidophiles, it is crucial to gain deeper insights into the adaptive mechanisms employed by these unique organisms. The existing literature reveals a notable gap in understanding the multi-stress conditions confronting acidophiles and their corresponding coping mechanisms. Therefore, the current review aims to illuminate the intricacies of the metabolic lifestyles of acidophiles within these demanding habitats, exploring how their energy demands contribute to habitat acidification. In addition, the unique adaptive mechanisms employed by acidophiles were emphasized, especially the pivotal role of monolayer membrane-spanning lipids, and how these organisms effectively respond to a myriad of stresses. Beyond mere survival, understanding the adaptive mechanisms of these unique organisms could further enhance their use in some biotechnological and environmental applications. Lastly, this review explores the strategies used to engineer these organisms to promote their use in industrial applications., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The transition from a fossil-based linear economy to a circular bioeconomy is no longer an option but rather imperative, given worldwide concerns about the depletion of fossil resources and the demand for innovative products that are ecocompatible. As a critical component of sustainable development, this discourse has attracted wide attention at the regional and international levels. Biorefinery is an indispensable technology to implement the blueprint of the circular bioeconomy. As a low-cost, non-waste innovative concept, the biorefinery concept will spur a myriad of new economic opportunities across a wide range of sectors. Consequently, scaling up biorefinery processes is of the essence. Despite several decades of research and development channeled into upscaling biorefinery processes, the commercialization of biorefinery technology appears unrealizable. In this review, challenges limiting the commercialization of biorefinery technologies are discussed, with a particular focus on biofuels, biochemicals, and biomaterials. To counteract these challenges, various process intensification strategies such as consolidated bioprocessing, integrated biorefinery configurations, the use of highly efficient bioreactors, simultaneous saccharification and fermentation, have been explored. This study also includes an overview of biomass pretreatment-generated inhibitory compounds as platform chemicals to produce other essential biocommodities. There is a detailed examination of the technological, economic, and environmental considerations of a sustainable biorefinery. Finally, the prospects for establishing a viable circular bioeconomy in Nigeria are briefly discussed., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Environmental pollution mitigation measure involving bioremediation technology is a sustainable intervention for a greener ecosystem biorecovery, especially the obnoxious hydrocarbons, xenobiotics, and other environmental pollutants induced by anthropogenic stressors. Several successful case studies have provided evidence to this paradigm including the putative adoption that the technology is eco-friendly, cost-effective, and shows a high tendency for total contaminants mineralization into innocuous bye-products. The present review reports advances in bioremediation, types, and strategies conventionally adopted in contaminant clean-up. It identified that natural attenuation and biostimulation are faced with notable limitations including the poor remedial outcome under the natural attenuation system and the residual contamination occasion following a biostimulation operation. It remarks that the use of genetically engineered microorganisms shows a potentially promising insight as a prudent remedial approach but is currently challenged by few ethical restrictions and the rural unavailability of the technology. It underscores that bioaugmentation, particularly the use of high cell density assemblages referred to as microbial consortia possess promising remedial prospects thus offers a more sustainable environmental security. The authors, therefore, recommend bioaugmentation for large scale contaminated sites in regions where environmental degradation is commonplace., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Despite the impressive gain in agricultural production and greater availability of food, a large portion of the world population is affected by food shortages and nutritional imbalance. This is due to abiotic stresses encountered by plants as a result of environmental-driven perturbations, loss of viability of starter cultures (probiotics) for functional foods during storage as well as the vulnerability of farm produce to postharvest pathogens. The use of compatible solutes (e.g., trehalose, proline, etc.) has been widely supported as a solution to these concerns. Trehalose is one of the widely reported microbial- or plant-derived metabolites that help microorganisms (e.g., biocontrol agents, probiotics and plant growth-promoting bacteria) and plants to tolerate harsh environmental conditions. Due to its recent categorization as generally regarded as safe (GRAS), trehalose is an essential tool for promoting nutrition-sensitive agriculture by replacing the overuse of chemical agents (e.g., pesticides, herbicides). Therefore, the current review evaluated the progress currently made in the application of trehalose in sustainable agriculture. The challenges, opportunities, and future of this biometabolite in food security were highlighted., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Antibiotic residues together with non-antibiotic drugs and heavy metals act as a selective pressure for the spread of antibiotic-resistant microorganisms (ARMs), antibiotic-resistant genes (ARGs), and mobile genetic elements (MGEs) during composting of livestock manure. ARMs, ARGs and MGEs have become emerging contaminants since they are regularly implicated in the majority of compost produced from livestock manure. The prevalence of these contaminants in agricultural soil receiving compost has drawn huge attention globally due to the risks they pose to the total environment. Although a large body of literature exists on the application of composting methods in minimizing the relative abundance of these contaminants, there is a paucity of information on the robustness, limitations and opportunities and threats of various composting protocols currently deployed. To address this knowledge gap, the current review compiled literature on the origin and mechanisms of the proliferation of ARMs, ARGs, and MGEs during composting of livestock manure. The effectiveness of current composting protocols in the reduction or removal of emerging contaminants was evaluated. Furthermore, the potential environmental impacts and human health risks of these contaminants following land application of compost were also presented. Finally, we propose some strategic approaches for the reduction of ARGs and MGEs during composting of livestock manure., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

The therapeutic application of bromelain is limited due to its sensitivity to operating conditions such as high acidity, gastric proteases in the stomach juice, chemicals, organic solvents and elevated temperature. We hypothesized that bromelain immobilized on probiotic bacterial spores would show enhanced therapeutic activity through possible synergistic or additive effects. In this study, the oedema inhibition potential of bromelain immobilized on probiotic Bacillus spores was compared to the free enzyme using the carrageenan paw oedema model with Wistar rats. In batch A rats (carrageenan-induced inflammation 30 min after receiving oral treatments), group 7 rats treated with a lower dose of spore-immobilized bromelain suspension showed the highest oedema inhibition, 89.20 ± 15.30%, while group 4 treated with a lower dose of free bromelain had oedema inhibition of 60.25 ± 13.00%. For batch B rats (carrageenan-induced inflammation after receiving oral treatment for three days), group 7 rats treated with a lower dose of spore-immobilized bromelain suspension showed higher inhibition percentage (81.94 ± 8.86) than group 4 treated with a lower dose of free bromelain (78.45 ± 4.46) after 24 h. Our results showed that used alone, the enzyme and the spores produced oedema inhibition and improved the motility of the rats. The spore-immobilized bromelain formulation performed approximately 0.9-fold better than the free bromelain and the free spores at the lower evaluated dose.

We investigated a number of microbiological activities in the soil to serve as biomonitoring tools in assessing the ecotoxicity of diesel-contaminated soil samples during the different periods of bioremediation. Sawdust was used as the biostimulant for the biodegradation of artificial diesel-polluted soil samples. Soil microbial population, soil microbial enzymatic activities (catalase, lipase, dehydrogenase, urease, phosphatase and β-glucosidase), soil microbial biomass carbon (MBC), nitrogen (MBN) and phosphorus (MBP), soil microbial respirometric index and total petroleum hydrocarbon (TPH) concentration were monitored to evaluate the efficiency of the bioremediation process. After a period of 56 d, total petroleum hydrocarbon content reduced from 14,221 to 270 mg/kg. The parameter estimation using the nth-order kinetic model revealed that the first-order rate constants ( k ) for TPH removal were 4.417 d -1 and 0.2670 d -1 for sawdust-amended and unamended soil, respectively. This implied that, the sawdust amendment resulted in reaction rate 16.5 times faster than unamended soil. Thus, the biological indicators were generally more pronounced in biostimulated soil than the attenuated soil. However, to evaluate the efficiency of the sawdust-assisted bioremediation, principal component analysis, which was used in selecting the most sensitive bioindicators. It was observed that microbial biomass carbon, catalase, lipase and dehydrogenase were the most responsive bioparameters. A positive relationship between TPH removal and the four most sensitive bioparameters suggests that the use of four biological activities have proven to be effective monitoring tools for evaluating the efficiency of a bioremediation strategy.

Multienzyme complex has attracted increased attention in biofuel technology. They offer solutions to effective degradation of complex plant material into fermentable sugars. Microorganisms, especially bacteria and fungi, are well studied for their ability to produce enzymes complex unlike yeast. Yeast strain isolated from mushroom farm was studied for simultaneous production of cellulase, xylanase and ligninase enzymes using lignocellulose waste as substrates. A response surface methodology (RSM) involving Box-Behnken design (BBD) was used to investigate interaction between variables (moisture content, inoculum size, initial pH, incubation time) that affect enzyme production. Crude filtrate was partially purified and characterised. Yeast strain identified as Saccharomyces cerevisiae SCPW 17 was finally studied. Evaluation of lignocellulose waste for enzyme complex production revealed corn cob to be most effective substrate for cellulase, xylanase and ligninase production with enzyme activity of 17.63 ± 1.45 U/gds, 29.35 ± 1.67 U/gds and 150.75 ± 2.01 μmol/min respectively. Time course study showed maximum enzyme complex production was obtained by day 6 with cellulase activity of 12.5 U/gds, xylanase 48.3 U/gds and ligninase 90.8 μmol/min. Using RSM involving BBD, maximum enzyme activity was found to be 19.51 ± 0.32 U/gds, 56.86 ± 0.38 U/gds, 408.17 ± 1.04 μmol/min for cellulaase, xylanase and ligninase respectively. The developed models were highly significant at probability level of P = 0.0001 and multiple correlation co-efficient (R 2 ) was 0.9563 for cellulase, 0.9532 for xylanase and 0.9780 for ligninase. Enzyme complex was stable at varying pH and temperature conditions. Saccharomyces cerevisiae (SCPW 17) studied produced enzyme complex which can be used for bioconversion of biomass to value-added chemicals., (© 2020 Published by Elsevier Ltd.)

Composting technology has become invaluable in stabilization of municipal waste due to its environmental compatibility. In this review, different types of composting methods reportedly applied in waste management were explored. Further to that, the major factors such as temperature, pH, C/N ratio, moisture, particle size that have been considered relevant in the monitoring of the composting process were elucidated. Relevant strategies to improve and optimize process effectiveness were also addressed. However, during composting, some challenges such as leachate generation, gas emission and lack of uniformity in assessing maturity indices are imminent. Here in, these challenges were properly addressed and some strategies towards ameliorating them were proffered. Finally, we highlighted some recent technologies that could improve composting., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

In this study, use of inorganic fertilizer (N.P.K) was compared with organic manure (compost) in the bioremediation of diesel-polluted agricultural soil over a two-month period. Renewal by enhanced natural attenuation was used as control. The results revealed that total petroleum hydrocarbon removal from polluted soil was 71.40 ± 5.60% and 93.31 ± 3.60% for N.P.K and compost amended options, respectively. The control (natural attenuation) had 57.90 ± 3.98% of total petroleum hydrocarbon removed. Experimental data fitted second order kinetic model adequately for compost amended option. The fertilizer amended option was found to be 1.04 times slower (k2 = 4.00 ± 1.40 × 10(-7)gmg(-1)d(-1), half-life = 28.15 d) than compost amended option (k2 = 1.39 ± 0.54 × 10(-5) gmg(-1)d(-1), half-life = 8.10 d) but 1.21 times (20.6%) faster than the control (k2 = 2.57 ± 0.16 × 10(-7) gmg(-1)d(-1), half-life = 43.81 d). The hydrocarbon utilizers isolated from the diesel contaminated soil were: Bacillus nealsoni, Micrococcus luteus, Aspergillus awamori, and Fusarium proliferatum. The phytotoxicity test showed that germination indices for natural attenuation (control), fertilizer (NPK) and compost amended options were 34%, 56%, and 89%, respectively., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

In the present study, laboratory scale bioremediation of dual purpose kerosene (DPK) hydrocarbon polluted soil using bulking agent (saw dust) was carried out. The effect of different parameters such as total petroleum hydrocarbon (TPH), dehydrogenase activity (DHase) and pH on bioremediation performance were evaluated. Studied parameters such as microbial dynamics, percentage degradation (95.20%), DHase (8.20 ± 0.43) were found to be higher in saw dust amended system and significantly differed with control at p < 0.05. Experimental data adequately fitted the first order kinetic thus, generated r(2) values (0.966), first order degradation constant (0.659 d(-1)), and degradation half-life t1/2 = ln2/k (1.05 d). Micrococcus luteus, Bacillus sp., Rhizopus arrhizus and Aspergillus sp. were isolated from the study. The use of saw dust as bulking agent greatly increased biodegradation rate and resulted in effective DPK hydrocarbon clean up. Therefore, saw dust could serve as an effective biostimulant towards improved bioremediation of hydrocarbon polluted environment., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Rhamnolipid biosurfactant production by Pseudomonas nitroreducens isolated from petroleum-contaminated soil was investigated. The effects of carbon, nitrogen and carbon to nitrogen ratio on biosurfactant production were examined using mineral salts medium as the growth medium. The tenso-active properties (surface activity and critical micelle concentrations of the produced biosurfactant were also evaluated. The best carbon source, nitrogen source were glucose and sodium nitrate giving rhamnolipid yields of 5.28 and 4.38 g l(-1), respectively. The maximum rhamnolipid production of 5.46 g l(-1) was at C/N (glucose/sodium nitrate) of 22. The rhamnolipid biosurfactant reduced the surface tension of water from 72 to ~37 mN/m. It also has critical micelle concentration of ~28 mg l(-1). Thus, the results presented in our reports show that the produced rhamnolipid can find wide applications in various bioremediation activities such as enhanced oil recovery and petroleum degradation.