Multi-product biorefinery from Arthrospira platensis biomass as feedstock for bioethanol and lactic acid production

With the aim to reach the maximum recovery of bulk and specialty bioproducts while minimizing waste generation, a multi-product biorefinery for ethanol and lactic acid production from the biomass of cyanobacterium Arthrospira platensis was investigated. Therefore, the residual biomass resulting from different pretreatments consisting of supercritical fluid extraction (SF) and microwave assisted extraction with non-polar (MN) and polar solvents (MP), previously applied on A. platensis to extract bioactive metabolites, was further valorized. In particular, it was used as a substrate for fermentation with Saccharomyces cerevisiae LPB-287 and Lactobacillus acidophilus ATCC 43121 to produce bioethanol (BE) and lactic acid (LA), respectively. The maximum concentrations achieved were 3.02 ± 0.07 g/L of BE by the MN process at 120 rpm 30 °C, and 9.67 ± 0.05 g/L of LA by the SF process at 120 rpm 37 °C. An economic analysis of BE and LA production was carried out to elucidate the impact of fermentation scale, fermenter costs, production titer, fermentation time and cyanobacterial biomass production cost. The results indicated that the critical variables are fermenter scale, equipment cost, and product titer; time process was analyzed but was not critical. As scale increased, costs tended to stabilize, but also more product was generated, which causes production costs per unit of product to sharply decrease. The median value of production cost was US$1.27 and US$ 0.39, for BE and LA, respectively, supporting the concept of cyanobacterium biomass being used for fermentation and subsequent extraction to obtain ethanol and lactic acid as end products from A. platensis

Towards an eco-friendly coffee rust control : compilation of natural alternatives from a nutritional and antifungal perspective

Hemileia vastatrix (HV) is the pathogen responsible for the coffee leaf rust (CLR) disease that has spread globally. CLR causes losses of up to a billion dollars annually and affects all types of crops regardless of their production regime (organic or inorganic). Additionally, smallholders produce approximately 80% of coffee in developing countries. The condition causes losses of up to a billion dollars annually. It affects all types of crops regardless of their production regime (organic or inorganic). Approximately 80% of coffee is produced by smallholders in developing countries. Until the 90s, shaded-production systems and native varieties were encouraged; however, the rapid spread of CLR has forced farmers to migrate towards inorganic schemes, mainly due to a lack of knowledge about natural alternatives to pesticides that can be implemented to control HV. Therefore, the purpose of this article is to compile the currently existing options, emphasizing two key factors that guarantee efficient rust control: selective fungicidal activity against HV and the nutrition of coffee crops. Thus, by comprehending how these natural compounds (such as plant, bacteria, fungi, animals, or algae metabolites) impact coffee rust proliferation. Furthermore, since a various range of biochar effects contributes to the control of foliar fungal pathogens through modification of root exudates, soil properties, and nutrient availability, which influence the growth of antagonist microorganisms, we present a review of the pathogen-suppressive effects of biochar, and new control strategies suitable for organic schemes can be developed.Publisher PDFPeer reviewe

Effects of light intensity and carbon dioxide on lipids and fatty acids produced by Synechocystis sp. PCC6803 during continuous flow

We studied the effects of light intensity (LI) and CO2 supply on pH and total lipid production and fatty acids by Synechocystis sp. PCC6803 during continuous-flow operation of a photobioreactor having continuous nutrient supply. The temperature was fixed at 30 °C, and the LI pattern mimicked a day/night light cycle from 0 to 1920 μmol/m2 s. The CO2 supply varied from1 to 5% v/v of total air. The total lipid content increased proportionally to LI, reaching a high content of 14% of dry weight (DW) at the highest LI at 3% CO2. In contrast, LI had no significant influence on the total fatty acid content, which was 3.4% ± 0.5% DW, measured as fatty acid methyl esters (FAMEs). Palmitic acid (C16:0) was the main fatty acid (52% of FAMEs), but γ-linolenic acid (C18:3n6) and linoleic acid (C18:2) were significant at 20% and 14% of total FAMEs, respectively. Also, a-linolenic acid (C18:3n3), oleic acid (C18:1), and palmitoleic acid (C16:1) represented 5%, 4%, and 4% of the total FAMEs, respectively. In case of C16:0, its highest content was achieved at LI of 400 to 1500 μmol/m2 s and pH media values from 7.2 to 8.8 (3% CO2). The highest formation of C16:1 and C18:1 (desirable for biodiesel production) occurred with LI up to 600 μmol/m2 s at pH 9 (3% CO2). Stearic acid (C18:0) and linoleic acid (C18:2) contents did not vary with LI or pH, but α-linolenic acid (C18:3n3) formation occurred with patterns opposite to C18:3n6, C16:0, and C16:1. LI of 400 to 1600 μmol/m2 s and pH range from 7.7 to 8.7 led to the highest values of C18:3n6 (0.8% DW), but C18:3n3 was suppressed by these conditions, supporting a desaturation pathway in Synechocystis. These results point to strategies to optimize LI, CO2, and pH, to enhance the fatty acid production profile for biofuel production. © 2015 The Authors. Published by Elsevier B.V

Application of microbial electrolysis cells to treat spent yeast from an alcoholic fermentation

Spent yeast (SY), a major challenge for the brewing industry, was treated using a microbial electrolysis cell to recover energy. Concentrations of SY from bench alcoholic fermentation and ethanol were tested, ranging from 750 to 1500mgCOD/L and 0 to 2400mgCOD/L respectively. COD removal efficiency (RE), coulombic efficiency (CE), coulombic recovery (CR), hydrogen production and current density were evaluated. The best treatment condition was 750mgCOD/LSY+1200mgCOD/L ethanol giving higher COD RE, CE, CR (90±1%, 90±2% and 81±1% respectively), as compared with 1500mgCOD/LSY (76±2%, 63±7% and 48±4% respectively); ethanol addition was significantly favorable (p value=0.011), possibly due to electron availability and SY autolysis. 1500mgCOD/LSY+1200mgCOD/L ethanol achieved higher current density (222.0±31.3A/m3) and hydrogen production (2.18±0.66 LH2/day/LReactor) but with lower efficiencies (87±2% COD RE, 71.0±.4% CE). Future work should focus on electron sinks, acclimation and optimizing SY breakdown. © 2015 The Authors. Published by Elsevier Ltd

Investigation of the geochemical evolution of groundwater under agricultural land: A case study in northeastern Mexico

Zona Citrícola is an important area for Mexico due to its citriculture activity. Situated in a sub-humid to humid climate adjacent to the Sierra Madre Oriental, this valley hosts an aquifer system that represents sequences of shales, marls, conglomerates, and alluvial deposits. Groundwater flows from mountainous recharge areas to the basin-fill deposits and provides base flows to supply drinking water to the adjacent metropolitan area of Monterrey. Recent studies examining the groundwater quality of the study area urge the mitigation of groundwater pollution. The objective of this study was to characterize the physical and chemical properties of the groundwater and to assess the processes controlling the groundwater's chemistry. Correlation was used to identify associations among various geochemical constituents. Factor analysis was applied to identify the water's chemical characteristics that were responsible for generating most of the variability within the dataset. Hierarchical cluster analysis was employed in combination with a post-hoc analysis of variance to partition the water samples into hydrochemical water groups: recharge waters (Ca-HCO3), transition zone waters (Ca-HCO3-SO4 to Ca-SO4-HCO3) and discharge waters (Ca-SO4). Inverse geochemical models of these groups were developed and constrained using PHREEQC to elucidate the chemical reactions controlling the water's chemistry between an initial (recharge) and final water. The primary reactions contributing to salinity were the following: (1) water-rock interactions, including the weathering of evaporitic rocks and dedolomitization; (2) dissolution of soil gas carbon dioxide; and (3) input from animal/human wastewater and manure in combination with by denitrification processes. Contributions from silicate weathering to salinity ranged from less important to insignificant. The findings suggest that it may not be cost-effective to regulate manure application to mitigate groundwater pollution. © 2014 The Authors

Development and Characterization of Nanoparticles-Loaded Bio-composites for Biomedical Settings

There is a dire need to engineer biologically robust constructs to meet the growing needs of 21st-century medical sector. The increasing (re)-emergence of human-health related pathogenic microbes has caused a havoc and serious challenge to health care services. In this context, herein, we report the development and characterization of various polymeric bio-composites with unique structural and functional attributes. For a said purpose, chitosan and graphene were used to engineer bio-composites, which were then functionalized by loading silver and platinum nanoparticles. A microwave-assisted approach was adopted to construct silver and platinum nanoparticles loaded graphene-based bio-composites. While, “one-pot” synthesis approach was used to engineer silver and platinum nanoparticles loaded chitosan-based bio-composites. As developed bio-composites were designated as GO-Ag-S1 to GO-Ag-S5 (silver nanoparticles loaded graphene-based bio-composites), GO-Pt-P1 to GO-Pt-P5 (platinum nanoparticles loaded graphene-based bio-composites), CHI-Ag-S1 to CHI-Ag-S5 (silver nanoparticles loaded chitosan-based bio-composites), and CHI-Pt-P1 to CHI-Pt-P5 (platinum nanoparticles loaded chitosan-based bio-composites). Finally, the nanoparticles loaded bio-composites of graphene and chitosan were subjected to characterization via UV-Visible spectrophotometric analysis, percent loading efficiency (%LE) analysis, Fourier-transform infrared (FTIR) spectroscopy, mechanical measurements, and antibacterial attributes. The UV-Visible spectrophotometric analysis revealed characteristic peaks appeared at the λmax 420 nm and 266 nm which belongs to the silver and platinum nanoparticles, respectively. The graphene-based bio-composites, i.e., GO-Ag-S3, GO-Ag-S4, and GO-Pt-P3 showed optimal %LE of 88, 92, and 89%, respectively. Whereas, CHI-Ag-S4, CHI-Pt-P3, and CHI-Pt-P4 bio-composites showed optimal %LE of 94, 86, and 94%, respectively. Two regions, i.e., (1) between 3600-3100 cm-1, and (2) between 1,800 and 1,000 cm-1 in the FTIR spectra were found of particular interest. The FTIR profile exposed the available functional moieties at the surface of respective bio-composites. Variable mechanical attributes of silver and platinum nanoparticles loaded bio-composites were recorded from the stress-strain curves. All developed bio-composites showed bactericidal activities up to certain extent against both test strains. As compared to the initial bacterial cell count (control value, i.e., 1.5 × 108 CFU/mL), the bio-composites with higher %LE showed almost complete inhibition, with a log reduction from 5 to 0, and bactericidal activities up to certain extent against both test strains, i.e., Bacillus subtilis (B. subtilis), and Escherichia coli (E. coli). In conclusion, the notable structural, functional, mechanical and antimicrobial attributes suggest the biomedical potentialities of newly in-house engineered silver and platinum nanoparticles loaded graphene and chitosan-based bio-composites

Greening the 21st century environmental engineering – A robust platform to mitigate contaminants of emerging concern

This special issue of Case Studies in Chemical and Environmental Engineering deals with the 21st century environmental engineering perspective to mitigate contaminants of emerging concern. Over the recent decades, a rampant industrial boom, urbanization, and an exponential increase in population growth resulted in numerous environmental impacts with water being one among the leading affected resources. All different kinds of pollutants, for example, organic compounds, heavy metals, dyes, pharmaceuticals and personal care products, pesticides, persistent/volatile organic compounds, petroleum hydrocarbons and toxic gases, have a paramount effect, either directly or indirectly, on human health and aquatic entities [1]. Human-made, agricultural, and industrial disposals play a substantial contribution in triggering wastewater pollution. Strategies for their affordable and efficient decontamination of these emerging pollutants have become the prime focus of academic researchers, industry, and government to constitute a sustainable human society. Classical techniques for determining and treatment of environmental contaminants are associated with several limitations, such as inefficiency, complex pretreatments, overall high process cost, generation of high sludge, and formation of highly toxic side-products [2]. Therefore, new, and state-of-the-art technologies possessing the advantages of detection, ease of use, and continuous degradation of environmental pollutants, are highly desirable.Peer reviewe

Photosynthetic bioenergy utilizing CO<inf>2</inf>: An approach on flue gases utilization for third generation biofuels

One of the most important industrial activities related to the greenhouse gases emissions is the cement manufacturing process, which produces large amounts of carbon dioxide (CO2). Only in 2010, 8% of CO2 global emissions were due to cement industry. In this work, the use of CO2 released by the cement sector is described as potential gas for microalgae culture since their biofixation efficiency is higher than terrestrial plants. Therefore, transformation of polluting gas fluxes into new and valuable products is feasible. In addition, bulk applications such as wastewater treatment and biofuels production can be coupled. Finally, microalgae biomass can be also used for the production of valuable compounds such as pigments, food supplements for both humans and animals, and fertilizers. In this review, flue gas emissions coupled to microalgae cultures are described. In addition, since microalgae can produce energy, the biorefinery concept is also reviewed. © 2014 The Authors

2019-nCoV/COVID-19 - Approaches to Viral Vaccine Development and Preventive Measures

The severity assessment of COVID-19 and transmissibility of newly emerged novel-Coronavirus (2019-nCoV) can effectively help and support to quantify the ongoing pandemic risks. Among several epidemiological measures against COVID-19 severity, the case fatality risk (CFR) assessment is an important measure to track record the overall proportion/ratio of the cumulative number of infected patients with the known outcome (confirmed, recovered, or deceased). Considering the ongoing fatality rate, several case-based preventive measures, Coronavirus protein visualization, and approaches to viral vaccine development are discussed herein. The prompt identification of high-risk entities to confront the uncertainty in the risk of death using the approaches highlighted, herein, is of utmost requirement to tackle the current COVID-19 severity. Moreover, the protein visualization available at the viral surface/ body can give further insight into the appropriate vaccine development

The Emergence of Novel-Coronavirus and its Replication Cycle - An Overview

Recently, a new viral-based infection has emerged as a respiratory disease caused by a novel (new) coronavirus that was first detected in Wuhan City, China. With any or many reasons, this newly emerged novel-Coronavirus (2019-nCoV) has now been recognized in more than 70 locations around the globe. The disease caused by 2019-nCoV has been named as “coronavirus disease 2019 – COVID-19”. Due to the rising number of confirmed 2019-nCoV infected cases and widespread detection, the World Health Organization (WHO) has announced 2019-nCoV as a threatening health concern, and urgent robust actions are of supreme interest to tackle this global health emergency. Owing to this new emergence, we know relatively little about 2019-nCoV, which is a highly pathogenic human pathogen. To completely overcome this life-threatening 2019-nCoV pathogen, further in-depth studies are needed to gain insight and complete understanding about its fast mode spread, replication, and pathogenesis. Since the first appearance and detection of 2019-nCoV and COVID-19, respectively, the current literature lacks the global perspective and replication cycle of 2019-nCoV. Thus, herein, an effort has been made to cover this literature gap. A proper understanding of the 2019-nCoV replication will further insight and strengthen the infection control measures, transmission prevention, and vaccine development, effectively