Biological Sources Research Articles

Noise levels in a changing Arctic Ocean and its implications for security

Arctic Ocean is undergoing an “Atlantification” of its oceanographic properties. Sea ice retreat and reduction of sea ice age will affect its underwater soundscape, with anthropogenic noise expected to increase due to the exploitation of new maritime routes. The CMRE’s Environmental and Operational Effectiveness Programme conducted a study of the new Arctic oceanographic conditions and ambient noise by deploying in 2021 and in 2022 different moorings equipped with passive acoustic recorders and oceanographic sensors. Data did not show a clear relation between sea-ice concentration and noise levels in the marginal ice zone. However, noise levels indicate that the possible presence of transmissions ducts might increase high frequency noise in the subsurface area. Seasonality and variations in the overall soundscapes were also evident by the presence of sounds from biological sources. In 2023, with the support of the NATO Office of the Chief Scientist, CMRE started a long-term scientific endeavor to study how climate change might affect the Alliance’s security in the maritime domain. A significant research effort is focused on the Arctic, and in June–July 2023 CMRE deployed three deep moorings for monitoring the acoustic-oceanographic conditions in the long term. [Work supported by the NATO Allied Command Transformation.]

Human auditory ecology: Extending hearing research to the perception of natural soundscapes by humans

A “natural soundscape” refers to the case where the contribution of acoustic events resulting from human activity can be considered as negligeable. As a consequence, natural soundscapes are only composed of biological sounds and geophysical sounds shaped by the specific way sounds propagate within the habitat under study. Within this framework, studying soundscape perception in humans aims at unveiling the relationship between the features of sound mixtures picked up at a given place and time by the peripheral auditory system of a human listener and the characteristics of the auditory percept evoked by these features. We will present a research program based on large and ecologically-valid acoustic databases recorded in protected areas aiming to (i) better understand the mechanisms involved in auditory perception of natural soundscapes; (ii) characterize and explain the effects of sensorineural hearing loss on perception of natural soundscapes; and (iii) assess the extent to which alterations in soundscape perception can be restored back to normal via hearing aids. This programme combines modelling and psychophysical methods to explore our ability to distinguish between habitat, time of day and season, to detect the presence of biological sound sources and to assess levels of biodiversity in the habitat.

Urea-Self Powered Biosensors: A Predictive Evolutionary Model for Human Energy Harvesting.

The objective of this study is to create a reliable predictive model for the electrochemical performance of self-powered biosensors that rely on urea-based biological energy sources. Specifically, this model focuses on the development of a human energy harvesting model based on the utilization of urea found in sweat, which will enable the development of self-powered biosensors. In the process, the potential of urea hydrolysis in the presence of a urease enzyme is employed as a bioreaction for self-powered biosensors. The enzymatic reaction yields a positive potential difference that can be harnessed to power biofuel cells (BFCs) and act as an energy source for biosensors. This process provides the energy required for self-powered biosensors as biofuel cells (BFCs). To this end, initially, the platinum electrodes are modified by multi-walled carbon nanotubes to increase their conductivity. After stabilizing the urease enzyme on the surface of the platinum electrode, the amount of electrical current produced in the process is measured. The optimal design of the experiments is performed based on the Taguchi method to investigate the effect of urea concentration, buffer concentration, and pH on the generated electrical current. A general equation is employed as a prediction model and its coefficients calculated using an evolutionary strategy. Also, the evaluation of effective parameters is performed based on error rates. The obtained results show that the established model predicts the electrical current in terms of urea concentration, buffer concentration, and pH with high accuracy.

Development of an epigenetic age predictor for costal cartilage with a simultaneous somatic tissue differentiation system

Age prediction from DNA has been a topic of interest in recent years due to the promising results obtained when using epigenetic markers. Since DNA methylation gradually changes across the individual’s lifetime, prediction models have been developed accordingly for age estimation. The tissue-dependence for this biomarker usually necessitates the development of tissue-specific age prediction models, in this way, multiple models for age inference have been constructed for the most commonly encountered forensic tissues (blood, oral mucosa, semen). The analysis of skeletal remains has also been attempted and prediction models for bone have now been reported. Recently, the VISAGE Enhanced Tool was developed for the simultaneous DNA methylation analysis of 8 age-correlated loci using targeted high-throughput sequencing. It has been shown that this method is compatible with epigenetic age estimation models for blood, buccal cells, and bone. Since when dealing with decomposed cadavers or postmortem samples, cartilage samples are also an important biological source, an age prediction model for cartilage has been generated in the present study based on methylation data collected using the VISAGE Enhanced Tool. In this way, we have developed a forensic cartilage age prediction model using a training set composed of 109 samples (19–74 age range) based on DNA methylation levels from three CpGs in FHL2, TRIM59 and KLF14, using multivariate quantile regression which provides a mean absolute error (MAE) of ± 4.41 years. An independent testing set composed of 72 samples (19–75 age range) was also analyzed and provided an MAE of ± 4.26 years. In addition, we demonstrate that the 8 VISAGE markers, comprising EDARADD, TRIM59, ELOVL2, MIR29B2CHG, PDE4C, ASPA, FHL2 and KLF14, can be used as tissue prediction markers which provide reliable blood, buccal cells, bone, and cartilage differentiation using a developed multinomial logistic regression model. A training set composed of 392 samples (n = 87 blood, n = 86 buccal cells, n = 110 bone and n = 109 cartilage) was used for building the model (correct classifications: 98.72%, sensitivity: 0.988, specificity: 0.996) and validation was performed using a testing set composed of 192 samples (n = 38 blood, n = 36 buccal cells, n = 46 bone and n = 72 cartilage) showing similar predictive success to the training set (correct classifications: 97.4%, sensitivity: 0.968, specificity: 0.991). By developing both a new cartilage age model and a tissue differentiation model, our study significantly expands the use of the VISAGE Enhanced Tool while increasing the amount of DNA methylation-based information obtained from a single sample and a single forensic laboratory analysis. Both models have been placed in the open-access Snipper forensic classification website.

Back to Old Books Toward Affordable Research: Homemade Phenol-Based Reagent for Triphasic RNA Purification.

Covid-19 crisis did hit many socio-economic aspects in the whole world. In the scientific research, the problem is getting even worse, since most of materials and consumable are allocated to the health sector. Many research laboratories around the world have big delay in receiving their purchases to accomplish their research projects. In the developing countries, the situation is much more difficult, since most of the funding resources are directed to the Covid-19 crisis and there is a notable increase in reagents' prices. Therefore, the aim of the present study is to make a homemade reagents for RNA purification from eukaryotic cells/tissues. The homemade phenol-based RNA extraction reagents were prepared using saturated phenol pH 4.3 (adjusted by 0.5M citrate buffer) and guanidine thiocyanate. To validate the phenol-based reagent, RNA was purified from different biological samples (cell line, tissues, and fungi) using homemade phenol-based versus a commercial one. Concentration of RNA samples extracted from the same number of cells were compared to assess the homemade preparation of phenol-based reagent. In conclusion, homemade phenol-based reagent is cost effective and comparableto the commercial one. Using homemade phenol-based, RNA extraction was successfully purified from different biological sources.

Activated carbon derived from oleander seeds supported ceria-zirconia mixed oxides for enhanced supercapacitive behaviour

Oxides of metals in combination with large surface area carbons have considered as a top contender for energy storage systems. In similar line, the present study explores the utilisation of a bi-metallic mixed oxide with activated carbon generated from biological sources as a promising electrode material for supercapacitor applications. The combination of activated carbon synthesized from the seeds of an Oleander plant that is readily available in North-east India, and the bimetallic mixed oxide (ceria-zirconia) synthesized through a conventional co-precipitation process is observed to have a specific capacitance of 270 F/g (at 1 A/g) and cycling stability with 98 % retention of specific capacitance up to 10,000 cycles. The produced electrode materials were characterised using scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and electrochemical techniques such as cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS). All the analyses revealed that the synthesized materials have the potential to be used as supercapacitor electrodes.

Enzymatic potential of endophytic fungi: xylanase production by Colletotrichum boninense from sugarcane biomass.

Endophytic fungi constitute a major part of the still unexplored fungal diversity and have gained interest as new biological sources of natural active compounds, including enzymes. Endophytic fungi were isolated from soybean leaves and initially screened on agar plates for the production of CMCase (carboxymethylcellulase), xylanase, amylase and protease. The highest Enzymatic Indexes (IE) were verified for xylanase (2.14 and 1.31) with the fungi M6-A6P5F2 and M12-A5P3F1.2 and CMCase (1.92 and 1.62) with the fungi M13-A9P2F1 and M12-A5P3F1.2, respectively. The production of xylanase and CMCase by the selected fungi was evaluated in submerged cultivation using beechwood xylan and carboxymethylcellulose (CMC), as well as sugarcane straw and bagasse in different ratios as carbon sources. Both types of lignocellulosic biomass proved to be good inducers of enzymatic activity. The best xylanase producer among the isolates was identified as Colletotrichum boninense. With this fungus, the highest xylanase activity was obtained with a sugarcane straw-bagasse mixture in a 50:50 ratio (383.63 U mL-1), a result superior to that obtained with the use of beechwood xylan (296.65 U mL-1). Regardingthe kinetic behavior of the crude xylanase, there was found optimal pH of 5.0 and optimal temperatures of 50°C and 60°C. At 40°C and 50°C, xylanase retained 87% and 76% of its initial catalytic activity, respectively. These results bring new perspectives on bioprospecting endophytic fungi for the production of enzymes, mainly xylanase, as well as the exploitation of agro-industrial by-products, such as sugarcane straw and bagasse.

From Biological Source to Energy Harvesting Device: Surface Protective Ionic Liquid Coatings for Electrical Performance Enhancement of Wood-Based Electronics.

This study explores task-specific ionic liquids (TSILs) in smart floor systems, highlighting their strong electrical rectification abilities and previously established wood preservative properties. Two types of TSILs, featuring a "sweet" anion and a terpene-based cation, were used to treat selected wood samples, allowing for a comparison of their physical and electrical performance with untreated and commercially treated counterparts. Drop shape analysis and scanning electron microscopy were employed to evaluate the surface treatment before and after coating. Near-IR was used to confirm the presence of a surface modifier, and thermogravimetric analysis (TGA) was utilized to assess the thermal features of the treated samples. The different surface treatments resulted in varied triboelectric nanogenerator (TENG) parameters, with the molecular structure and size of the side chains being the key determining factors. The best results were achieved with TSILs, with the instantaneous voltage increasing by approximately five times and the highest voltage reaching 300 V under enhanced loading. This work provides fresh insights into the potential application spectrum of TSILs and opens up new avenues for directly utilizing tested ionic compounds in construction systems.

Fish Waste: A Potential Source of Biodiesel

The continuously increasing energy requirement on one hand and the incessant depletion of non-renewable fossil fuels on the other urge us to focus on alternative renewable energy sources such as biofuels. Biofuels including biodiesel, bioethanol, biobutanol, biohydrogen, etc., are generated from different biological sources, and their waste which stands as the best alternative in the present scenario. Specifically, the utilization of biological wastes as raw materials for the production of biofuels is considered as best waste management practice. To date, most of the biodiesel production research has been carried out with plant, algal, and microbial samples, or their waste. It is a well-known fact that diesel can also be produced from specific oily fish and their waste using different methods. In addition, fish waste constitutes a major quantity compared to other food waste which is a serious concern. Furthermore, the disposal of fish waste shows an impact on both the environment and the economy. Hence, the development of protocols for the efficient production of biodiesel from fish waste is the ultimate goal. However, insufficient knowledge and less effort in the conversion of fish waste to biodiesel impede the achievement of this goal. Therefore, this review intends to summarize the mechanism of biodiesel production from fish waste. Also, various physico-chemical factors involved in biodiesel production from fish waste were discussed. In addition, research on biodiesel generation from various fish wastes or waste fish oil was also emphasized in detail, which will be helpful for commercial practice. Overall, this information will be useful for improvement in biodiesel production from fish waste.

Bio-polymer modified bitumen

Bitumen is a key constitutive material in asphalt pavements. It binds together the rock scaffolding of a pavement. Bitumen provides asphalt pavement with flexibility and enables it to respond to traffic loading and return to its original condition after the loading, i.e. bitumen restores/repairs the damage. In Porous Asphalt (PA) or Stonemastic Asphalt Mix (SMA) asphalt mixtures, due its open graded structure, bitumen modifiers are used to improve or restore bitumen physical and mechanical performance. Traditionally bitumen modifiers are made with products of crude oil, such as: ethylene vinyl acetate (EVA) copolymers and styrene–butadiene–styrene (SBS). As crude oil production declines and the environmental and financial costs of crude oil extraction increase, there is a need to identify environmentally sustainable alternatives to use in bitumen. Bitumen modifiers generated from biological sources offer an environmentally friendly and economically viable alternative to crude oil based bitumen modifiers. This paper describes how PHBV (poly-3-hydroxybutyrate-co-3-hydroxyvalerate), a bio-based co-polymer, might be used as an alternative bitumen modifier. The effect of PHBV on 70/100pen was investigated for this paper. The chemical and physical effect of the PHBV on the bitumen performance was investigated using Gel Permeation Chromatography, Fourier Transformed Infrared Spectroscopy, Differential Scanning Calorimetry, microscopic imaging and Dynamic Shear Rheometer tests. The results indicate that PHBV has significant potential as a bitumen bio-polymer modifier.

The Biological Functions and Intestinal Inflammation Regulation of IL-21 in Grass Carp (Ctenopharyngodon idella) during Infection with Aeromonas hydrophila.

Interleukin (IL) 21 is a pleiotropic cytokine that plays an important role in regulating innate and adaptive immune responses. In fish, the biological functions and cell source of IL-21 remain largely unknown. In this study, we performed qRT-PCR, Western blotting and immunofluorescent microscopy to examine the expression of IL-21 at the mRNA and protein levels. We found that il21 expression was induced in the primary head kidney leukocytes of grass carp (Ctenopharyngodon idella) by heat-inactivated Aeromonas hydrophila (A. hydrophila) and LPS and in tissues after infection with A. hydrophila. Recombinant IL-21 protein produced in the CHO-S cells was effective in elevating the expression of antibacterial genes, including β-defensin and lysozyme, and, interestingly, inhibited the NF-κB signaling pathway. Furthermore, we investigated the response of the IL-21 expressing cells to A. hydrophila infection. Immunofluorescent assay showed that IL-21 protein was detected in the CD3γ/δ T cells and was markedly accumulated in the anterior, middle and posterior intestine. Collectively, the results indicate that IL-21 plays an important role in regulating the intestinal inflammation induced by bacterial infection in grass carp.

Charge variants of proposed biosimilar to Omalizumab: Isolation, purification and analysis by HPLC methods

Omalizumab (Xolair) is a humanized monoclonal antibody derived by recombinant DNA technology. It binds specifically to immunoglobulin E (IgE) which plays a major role in allergic reaction by releasing histamine and other inflammatory factors from mast cells. Omalizumab binds circulatory IgE with high affinity and prevents from its binding to mast cell receptor. Charge variants are one of the critical quality attributes (CQAs) in biological drug development and sources of heterogeneity which needs to be considered in biosimilarity assessment. In this study, biosimilar product of Xolair was expressed in mammalian cell culture process in laboratory to isolate charge variants (acidic, main peak and basic). Different charge variants were isolated from intermediate purified biosimilar product of Xolair. Isolated charge variants were purified with preparative cation exchange chromatography technique and characterized with different analytical tools includes size exclusion chromatography (SEC-HPLC) and cation exchange chromatography (CEX-HPLC). Purity of acidic, main peak and basic variants was 99.58%, 99.98% and 98.64% respectively as per SEC-HPLC and according to CEX-HPLC purity was 94.25%, 95.58% and 91.33% respectively. The study data indicates that isolated charge variants were purified with desired purity and can be further used for process characterization, in vitro potency and in vivo kinetics studies.

Microfluidic single-cell measurements of oxidative stress as a function of cell cycle position.

Single-cell measurements routinely demonstrate high levels of variation between cells, but fewer studies provide insight into the analytical and biological sources of this variation. This is particularly true of chemical cytometry, in which individual cells are lysed and their contents separated, compared to more established single-cell measurements of the genome and transcriptome. To characterize population-level variation and its sources, we analyzed oxidative stress levels in 1278 individual Dictyostelium discoideum cells as a function of exogenous stress level and cell cycle position. Cells were exposed to varying levels of oxidative stress via singlet oxygen generation using the photosensitizer Rose Bengal. Single-cell data reproduced the dose-response observed in ensemble measurements by CE-LIF, superimposed with high levels of heterogeneity. Through experiments and data analysis, we explored possible biological sources of this heterogeneity. No trend was observed between population variation and oxidative stress level, but cell cycle position was a major contributor to heterogeneity in oxidative stress. Cells synchronized to the same stage of cell division were less heterogeneous than unsynchronized cells (RSD of 37-51% vs 93%), and mitotic cells had higher levels of reactive oxygen species than interphase cells. While past research has proposed changes in cell size during the cell cycle as a source of biological noise, the measurements presented here use an internal standard to normalize for effects of cell volume, suggesting a more complex contribution of cell cycle to heterogeneity of oxidative stress.

Hydrogen Sulfide: An Emerging Regulator of Oxidative Stress and Cellular Homeostasis-A Comprehensive One-Year Review.

Hydrogen sulfide (H2S), traditionally recognized as a toxic gas, has emerged as a critical regulator in many biological processes, including oxidative stress and cellular homeostasis. This review presents an exhaustive overview of the current understanding of H2S and its multifaceted role in mammalian cellular functioning and oxidative stress management. We delve into the biological sources and function of H2S, mechanisms underlying oxidative stress and cellular homeostasis, and the intricate relationships between these processes. We explore evidence from recent experimental and clinical studies, unraveling the intricate biochemical and molecular mechanisms dictating H2S's roles in modulating oxidative stress responses and maintaining cellular homeostasis. The clinical implications and therapeutic potential of H2S in conditions characterized by oxidative stress dysregulation and disrupted homeostasis are discussed, highlighting the emerging significance of H2S in health and disease. Finally, this review underscores current challenges, controversies, and future directions in the field, emphasizing the need for further research to harness H2S's potential as a therapeutic agent for diseases associated with oxidative stress and homeostatic imbalance. Through this review, we aim to emphasize H2S's pivotal role in cellular function, encouraging further exploration into this burgeoning area of research.

Antimicrobial Peptides: The Production of Novel Peptide-Based Therapeutics in Plant Systems.

The increased prevalence of antibiotic resistance is alarming and has a significant impact on the economies of emerging and underdeveloped nations. The redundancy of antibiotic discovery platforms (ADPs) and injudicious use of conventional antibiotics has severely impacted millions, across the globe. Potent antimicrobials from biological sources have been extensively explored as a ray of hope to counter the growing menace of antibiotic resistance in the population. Antimicrobial peptides (AMPs) are gaining momentum as powerful antimicrobial therapies to combat drug-resistant bacterial strains. The tremendous therapeutic potential of natural and synthesized AMPs as novel and potent antimicrobials is highlighted by their unique mode of action, as exemplified by multiple research initiatives. Recent advances and developments in antimicrobial discovery and research have increased our understanding of the structure, characteristics, and function of AMPs; nevertheless, knowledge gaps still need to be addressed before these therapeutic options can be fully exploited. This thematic article provides a comprehensive insight into the potential of AMPs as potent arsenals to counter drug-resistant pathogens, a historical overview and recent advances, and their efficient production in plants, defining novel upcoming trends in drug discovery and research. The advances in synthetic biology and plant-based expression systems for AMP production have defined new paradigms in the efficient production of potent antimicrobials in plant systems, a prospective approach to countering drug-resistant pathogens.

A brief review on the mechanisms and approaches of silk spinning-inspired biofabrication.

Silk spinning, observed in spiders and insects, exhibits a remarkable biological source of inspiration for advanced polymer fabrications. Because of the systems design, silk spinning represents a holistic and circular approach to sustainable polymer fabrication, characterized by renewable resources, ambient and aqueous processing conditions, and fully recyclable "wastes." Also, silk spinning results in structures that are characterized by the combination of monolithic proteinaceous composition and mechanical strength, as well as demonstrate tunable degradation profiles and minimal immunogenicity, thus making it a viable alternative to most synthetic polymers for the development of advanced biomedical devices. However, the fundamental mechanisms of silk spinning remain incompletely understood, thus impeding the efforts to harness the advantageous properties of silk spinning. Here, we present a concise and timely review of several essential features of silk spinning, including the molecular designs of silk proteins and the solvent cues along the spinning apparatus. The solvent cues, including salt ions, pH, and water content, are suggested to direct the hierarchical assembly of silk proteins and thus play a central role in silk spinning. We also discuss several hypotheses on the roles of solvent cues to provide a relatively comprehensive analysis and to identify the current knowledge gap. We then review the state-of-the-art bioinspired fabrications with silk proteins, including fiber spinning and additive approaches/three-dimensional (3D) printing. An emphasis throughout the article is placed on the universal characteristics of silk spinning developed through millions of years of individual evolution pathways in spiders and silkworms. This review serves as a stepping stone for future research endeavors, facilitating the in vitro recapitulation of silk spinning and advancing the field of bioinspired polymer fabrication.

Biomethanol production from renewable resources: a sustainable approach.

The abundant availability of various kinds of biomass and their use as feedstock for the production of gaseous and liquid biofuels has been considered a viable, eco-friendly, and sustainable mode of energy generation. Gaseous fuels like biogas and liquid fuels, e.g., bioethanol, biodiesel, and biomethanol derived from biological sources, have been theorized to produce numerous industrially relevant organic compounds replacing the traditional practice of employing fossil fuels as a raw material. Among the biofuels explored, biomethanol has shown promising potential to be a future product addressing multifactorial issues concerning sustainable energy and associated process developments. The presented mini-review has explored the importance and application of biomethanol as a value-added product. The biomethanol production process was well reviewed by focusing on different thermochemical and biochemical conversion processes. Syngas and biogas have been acknowledged as potential resources for biomethanol synthesis. The emphasis on biochemical processes is laid on the principal metabolic pathways and enzymatic machinery involved or used by microbial physiology to convert feedstock into biomethanol under normal temperature and pressure conditions. The advantage of minimizing the cost of production by utilizing suggested modifications to the overall process of biomethanol production that involves metabolic and genetic engineering in microbial strains used in the production process has been delineated. The challenges that exist in our current knowledge domain, impeding large-scale commercial production potential of biomethanol at a cost-effective rate, and strategies to overcome them along with its future scenarios have also been pointed out.

Quantifying exchangeable base cations in permafrost: a reserve of nutrients about to thaw

Abstract. Permafrost ecosystems are limited in nutrients for vegetation development and constrain the biological activity to the active layer. Upon Arctic warming, permafrost thaw exposes large amounts of soil organic carbon (SOC) to decomposition and minerals to weathering but also releases organic and mineral soil material that may directly influence the soil exchange properties (cation exchange capacity, CEC, and base saturation, BS). The soil exchange properties are key for nutrient base cation supply (Ca2+, K+, Mg2+, and Na+) for vegetation growth and development. In this study, we investigate the distributions of soil exchange properties within Arctic tundra permafrost soils at Eight Mile Lake (Interior Alaska, USA) because they will dictate the potential reservoir of newly thawed nutrients and thereby influence soil biological activity and vegetation nutrient sources. Our results highlight much lower CEC density in surface horizons (∼9400 cmolc m−3) than in the mineral horizons of the active layer (∼16 000 cmolc m−3) or in permafrost soil horizons (∼12 000 cmolc m−3). Together, with the overall increase in CEC density with depth and the overall increase in BS (percentage of CEC occupied by exchangeable base cations Ca2+, K+, Mg2+, and Na+) with depth (from ∼19 % in organic surface horizons to 62 % in permafrost soil horizons), the total exchangeable base cation density (Ca2+, K+, Mg2+, and Na+ in g m−3) is up to 5 times higher in the permafrost than in the active layer. More specifically, the exchangeable base cation density in the 20 cm upper part of permafrost about to thaw is ∼850 g m−3 for Caexch, 45 g m−3 for Kexch, 200 g m−3 for Mgexch, and 150 g m−3 for Naexch. This estimate is needed for future ecosystem prediction models to provide constraints on the size of the reservoir in exchangeable nutrients (Ca, K, Mg, and Na) about to thaw. All data described in this paper are stored in Dataverse, the online repository of Université catholique de Louvain, and are accessible through the following DOI: https://doi.org/10.14428/DVN/FQVMEP (Mauclet et al., 2022b).

Application of artificial neural networks for enhancing Aspergillus flavipes lipase synthesis for green biodiesel production

Biodiesel is a sustainable, and renewable alternative to fossil fuels that can be produced from various biological sources with the aid of lipases. This study developed a simple and novel fungal system for lipase biosynthesis to be used for catalyzing the oily residuals into biodiesel, employing the artificial neural network (ANN), and semi-solid-state fermentation (SSSF). Nigella sativa was selected among agro-industrial oily residuals as a substrate for lipase biosynthesis by Aspergillus flavipes MH47297. The effect of cultural humidity (X1), the surfactant; Brij 35 (X2), and inoculum density (X3) on lipase biosynthesis were researched based on the matrix of Box-Behnken design (BBD). The ANN together with a new fungal candidate and SSSF were then applied for the first time to model the biosynthesis process of lipase. The optimum predicted cultural conditions varied according to the model. The optimum predicted conditions were estimated separately by BBD (X1 = 5.8 ml water/g, X2 = 46.6 μl/g, and X3 = 62156610 spore/g) and ANN (X1 = 5.4 ml water/g, X2 = 54.2 μl/g, and X3 = 100000000 spore/g) models. Based on the modeling process, the response of lipase was calculated to be 214.95 (BBD) and 217.72 U (ANN), which revealed high consistency with the experimental lipase yield (209.13 ± 3.27 U for BBD, and 218 ± 2.01 U for ANN). Despite both models showing high accuracy, ANN was more accurate and surpassed the BBD model. Gas chromatography analysis showed that lipase successfully converted corn oil to biodiesel (29.5 mg/l).

Simultaneous Production and Consumption of Soil N2O Creates Complex Effects on Its Stable Isotope Composition

AbstractThe stable N and O isotope composition of soil and soil‐respired N2O is increasingly measured, yet a solid theoretical framework for interpreting the data remains to be developed. Here, the physical processes that affect soil N2O and its isotopes are embedded in a diffusion/reaction model. Numerical experiments are compared to data to demonstrate how various soil processes influence depth profiles and surface fluxes of soil N2O, δ15NN2O, and δ18ON2O. Model predictions and data suggest that the isotope composition of the net N2O soil flux, in soils that have N2O consumption, is a function of the net flux rate, and the isotope differences between the atmosphere and the biological source. Asymptotically large negative or positive δ15Nflux and δ18Oflux values occur as the net soil N2O flux approaches zero from positive or negative flux rates, respectively. This implies that the isotopic imprint of soil fluxes on the global atmospheric N2O pool is more variable than previously suggested. Additionally, the observed isotope values in static flux chambers are possibly complicated by the fact that consumption fluxes increase as the concentration in the chambers increases. This work reveals that even simple chamber flux measurements may possess isotope effects imparted by consumption during the chamber measurement and suggests ways to experimentally test this possibility. Additionally, simple methods to estimate depth‐dependent net production/consumption and its isotope effects are suggested. However, understanding the gross rates of the production and consumption of soil N2O remains an elusive goal.