Corncob pyrochar activated with steam (CCA) and nonactivated corncob pyrochar (NCC) were produced and characterized. The performance of the best material was tested in a dual-chambered microbial fuel cell (MFC) as an electrode for bioelectricity generation using wet torrefaction wastewater as substrate. Pyrolysis of 80.3 g of dried corncobs was carried out at 600 • C under a constant N 2 flow of 3 L min −1 for 30 min and the resulting pyrochar was activated using steam also at 600 • C. Voltage and current outputs from the MFC were recorded daily for 18 days. The proximate and Brunauer-Emmett-Teller (BET) surface area analyses revealed that CCA had the highest fixed carbon content of 71.9 % and higher surface area of 104.0 m 2 g −1 respectively. A larger pore diameter of 1.9 × 10 −3 µm was also recorded with the CCA than 1.2 × 10 −3 µm for NCC. The MFC produced a maximum power output of 21.5 mW. The physicochemical analyses of the wastewater effluent revealed an increased electrical conductivity from 1724 to 3460 µS cm −1 with a significant decrease by 91.9% in the total organic carbon (TOC) from 3700 to 298 mg L −1 . Steam activation increases the surface area, porosity, stability and redox reversibility of the corncob pyrochar. Therefore, steam-activated corncob pyrochar performed well in MFCs due to the high power output observed. K E Y W O R D Sbiobased corncob pyrochar, electrodes in MFC, power output of MFC, steam activation, wastewater This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

This study was conducted to screen for pectinase production by Aspergillus niger isolated from soil samples collected from three different locations within Ahmadu Bello University, Zaria, namely; botanical garden, refuse dump and sheep pen sites. A total of fifteen (15) soil samples were collected from different locations and used for isolation by a cultural method. Isolates suspected to be Aspergillus niger were further identified by microscopic examination of the lactophenol cotton blue stained-preparation and slide culture technique. The isolates were then screened in a pectin-containing medium for their pectinase activity. The isolates were further subjected to pectinase production using citrus pectin as the substrate under submerged fermentation conditions. Seven (7) isolates were confirmed to be Aspergillus niger with percentage occurrence of 60% each from sheep pen (SP) and refuse dumpsites (RD), and 20% from the botanical garden (BG). Aspergillus niger RD3 produced the highest zone of pectin hydrolysis (53 ± 1.1 mm) while isolate RD5 produced the lowest (35 ± 3.1 mm). Under submerged fermentation conditions, Aspergillus niger SP5 had the highest pectinase activity of 2.92 U/mL while isolate RD4 had the lowest pectinase activity of 1.29 U/mL. Aspergillus niger can be readily isolated from various soil types with the highest frequency in soils from sheep pen and refuse dumpsites. All the Aspergillus niger isolates demonstrated the potential for pectinase production. The study reveals the potential of various Aspergillus niger isolates from different soil in the production of pectinase.

In this study, different species of fungi associated with oil and non-oil Garri were isolated at Mudalawal market, Bauchi State, Nigeria. A total of eight different samples were obtained inside a sterile container and transported to the microbiology laboratory at Abubakar Tatari Ali Polytechnic Bauchi state for analysis. Malt Extract Agar was used for the isolation and identification; about five fungal species were isolated and identified using the standard method of Microbiological techniques. Penicillium spp. (26.9 %) had the highest occurrence in oil and non-oil Garri, followed by Aspergillus spp. (23.1 %), and Rhizopus spp. (19.2 %) with Fusarium spp. and Mucor spp. having the minor frequency of 15.4 %. Higher fungal species were isolated from non-oil Garri compared to oil Garri samples. Moisture content recorded showed higher Oil Garri than in the Non-oil Garri. The fungi isolated were characterized and identified based on their morphological and colonial appearance. The results show that consumers are exposed to the risk of aflatoxin poisoning. Efforts should therefore be made to improve the quality of Cassava by addressing its handling and processing practices.

There are increasing demands for syngas production. Fossil-based fuels are expensive and environmentally unfriendly. Affordable, sustainable, and environmentally healthy alternatives and sustainable fuel sources are needed. This study focused on producing tor-chars from two different tropical biomasses (from Nigeria, West Africa), which were torrefied and characterized to improve their properties for potential use as sustainable feedstocks in an entrained flow gasifier for syngas production. Torrefaction temperatures of 230, 240, 250, and 270 °C and residence times of 30 and 60 min were used to torrefy sundried sorghum straw (SS) and millet straw (MS) at particle size ≤5 mm. The properties of torrefied MS and SS improved significantly due to torrefaction. The optimum conditions for pretreatment of sundried MS and SS were 240 °C and 60 min, at which increased energy density significantly compensated for the severe mass loss and significant degradation of hemicellulose and cellulose. Under these conditions, the respective mass and energy yields were 53 wt% and 75% for millet straw and 49 wt% and 75% for sorghum straw. The O:C atomic ratio decreased to 0.3 in MS tor-chars and 0.2 in SS tor-chars resulting in higher heating values of 25 MJ kg −1 and 27 MJ kg −1 , respectively. Under optimum conditions, the ash content increased by 107% to be approximately 7 wt% in MS tor-char, and by 118% to about 7 wt% in SS tor-char. These properties are promising for potential feedstocks in co-firing plants or gasification systems.

Microbial fuel cell (MFC) is an evolving technology for anaerobic bioenergy generation using electrodes and organic wastewater as a feedstock for catabolic activities of electrogenic bacteria and subsequent electricity generation. The search for suitable inexpensive electrode materials remains the leading interest of researchers in this field. The work here focused on comparative bioelectricity generation from HTC process water (pH = 5.99) and treated–biogas digestate (pH = 7.97) using locally developed corncob pyrochar electrodes and graphite in dual-chambered microbial fuel cells (MFC). The electrodes used in this study were graphite rod (non-porous and very low surface area), KOH–activated corncob pyrochar (KAC) of BET surface area, 1626 m2 g-1 and steam activated corncob pyrochar (SAC) with 485.8 m2 g-1. The highest power outputs achieved were 323.8 µW and 316.8 µW from HTC process water with SAC and KAC electrodes respectively at an external load of 47 Ω. The initial COD (48780 mg L-1), DOC (4000 mg L-1), and TNb (5600 mg L-1) of the biogas digestate decreased significantly to 36405, 3610 and 4300 mg L-1 respectively in the MFC with KOH-activated corncob pyrochar electrodes. The MFC operated with KAC electrode and treated biogas digestate was the most efficient having Coulombic efficiency of 75 % in a comparatively shorter residence time of MFC operation than the MFC with SAC electrode which had a lower Coulombic efficiency of 64 %.

Abstract:Many different biomass of agricultural origin holds remarkable potential for conversion into valuable products thereby presenting a double sharp edge importance of sustainable resource supply and environmental protection. Glutamic acid was produced from rice husk using a novel strain of Corynebacterium glutamicum and effects of parameters optimization such as substrate concentration, temperature, pH and inoculum size were determined during the fermentation process. The wild-type (Novel) strain was inoculated into 13 g/L of the pre-treated rice husk previously added to basal medium (pH 7.2), after which fermentation began. Fermentation broth from each flask was taken aseptically after 96 h and was assayed qualitatively and quantitatively. The acid-treated and alkali-treated rice husk gave the best glutamic acid yield of 10.40g/L and 9.08g/L respectively with the wild-type strain under predetermined optimum fermentation conditions. Out of the four parameters optimized, only substrate concentration was not found to be significant on the performance of the wild-type strain in glutamate production (p ˃ 0.05). Acid-treated rice husk hydrolysate was found to be a better substrate for L-glutamate production by the wild-type strain of C. glutamicum under the optimum fermentation conditions determined.

SARS-CoV-2 is a novel coronavirus responsible for the current COVID-19 pandemic. It is the seventh coronavirus known to infect humans (the previous human coronaviruses are HCoV-OC43, HCoV-229E, HCoV-HKU1, HCoV-NL63, SARS-CoV and MERS-CoV) and the third human coronavirus known to cause severe illness in human after SARS-CoV and MERS-CoV. These three coronaviruses have caused three different severe respiratory diseases outbreaks within the last two decades: SARS in 2002-2003, MERS in 2012 and COVID-19 in 2020. The aim of this review was to summarize information on the genome and structure of SARS-CoV-2. SARS-CoV-2 is an enveloped positive-sense single-stranded RNA virus with a crown-like appearance due to the presence of spike glycoprotein on the envelope. The nonsegmented genome of SARS-CoV-2 of approximately 30kb encodes two large polyproteins, four main structural proteins namely spike, membrane, envelope and nucleocapsid proteins as well as several accessory proteins. Analysis of SARS-CoV-2 genome shows that it is highly related to coronavirus from the bat (96%), pangolin (91%) and SARS-CoV (80%). Variants of SARS-CoV-2 have evolved continuously as a result of genetic mutations and are circulating worldwide. These variants have varying degrees of transmissibility, disease severity, susceptibility to therapeutics and detection by diagnostic tools. Understanding the structure and genome of SARS-CoV-2 is important in the control, management, diagnosis and treatment of COVID-19 as well as vaccine development.

Despite large varieties of commercially available electrodes, only few are suitable for electro-active bacterial colonization during biofilm formation in microbial fuel cells (MFCs), and most of these electrodes are cost prohibitive. Hence there is need to search for low-cost alternative electrodes for MFCs. Pyrochars were produced in this study by pyrolysis (600 °C and a continuous flow rate of 3 L/min of nitrogen gas for 30 min) and subsequently steam and potassium hydroxide (KOH) activation of the pyrochar at 600 °C were carried out accordingly. Physicochemical, structural, and electrochemical properties of the activated and non-activated pyrochars were determined according to standardized analytical methods. According to BET, 1626 m 2 g -1 surface area and 14.74 Å pore diameter were obtained from the KOH-activated pyrochar which was also the most conductive (0.26 S m -1 ). Chemical activation of pyrochar with KOH resulted in increased electrical conductivity (EC), pore diameter, and most importantly the material's surface area according to the findings. In conclusion, KOH-activated corncob pyrochar holds potentials for producing electrode materials with desirable characteristics for successful application in MFC compared to the non-activated and steam-activated pyrochars of the same biomass.