Search

Methane production from wastes, like sewage sludge and fruit and vegetable wastes, has double benefits; first is minimizing these wastes and second is energy recovery. The goal of this research is to enhance methane yield from anaerobic co-digestion of primary sludge (PS) with fruit and vegetable wastes (FVW) in Egypt using different mixture and various inoculum types. Bio-chemical methane potential (BMP) tests were conducted in a 500-mL glass reactor under mesophilic conditions (35–37 °C). In the first BMP tests, six mixtures with PS to FVW ratios of 100:0, 70:30, 50:50, 30:70, 20:80, and 0:100 (based on volatile solids) were performed to obtain the best mixture for an optimal methane production. In the second BMP tests, three types of inoculum (fresh cow manure, activated sludge, and excess sludge) were used to identify the optimal inoculum for the greatest methane production. The highest methane yield was observed at PS to FVW ratio of 50:50 (141 mL/g VS), which was higher than the individual digestion of the other used feedstock. However, the minimum methane yield was recorded at PS to FVW ratio of 20:80. On the other hand, using the activated sludge as inoculum improved the methane yields from anaerobic co-digestion of PS with FVW compared with the other types of inoculum. Statistical analysis of the results was conducted using ANOVA test. The results conducted that the production of methane was improved by anaerobic co-digestion of PS with FVW and using the activated sludge as inoculum. [ABSTRACT FROM AUTHOR]

• Critical factors impacting microbial methanogenesis cells (MMCs) were analyzed. • CH4 production and set potentials or current densities showed weak relationships. • Using metal catalysts for the anode impacted MMC performance. • The use of mixed anaerobic cultures was sufficient for the MMC inoculum. • Catholyte pH control and CO2 supply methods were critical operation factors. With increasing attention on carbon capture and utilization (CCU) technologies for the conversion of CO 2 into chemical products, microbial methanogenesis cells (MMCs) have been extensively studied over the past few decades for biomethane production. Using rapidly accumulating data for MMCs with varying configurations and operating conditions, a comprehensive analysis was conducted here to investigate the critical factors that influence methane production rates (MPR) in these systems. A comparison of MPR and set potentials or current densities showed weak linear relationships (R2 < 0.6, p < 0.05), indicating the significant contributions of other important factors impacting methane production. A non-quantitative analysis of these additional parameters indicated the potential importance of using metal catalysts for anode materials where oxygen evolution reaction occurs, while most previous MMC research focused more on cathode materials where the biocatalytic reaction occurs. The use of undefined mixed anaerobic cultures as inocula was found to be sufficient for producing high MPRs, as the electrochemical environment at the cathode provides a strong selective pressure to converge on desirable methanogenic cultures. Other operational parameters, such as catholyte pH control and CO 2 supply methods, were also important factors impacting MPR in MMCs, indicating the cumulative impact of these various factors will require careful consideration in future research. [Display omitted] [ABSTRACT FROM AUTHOR]

Highlights • Spore inoculated culture showed higher antibacterial activity than vegetative cells. • The endophytic colonization level was enhanced by soil drenching with 32a spores. • Biocontrol activity was improved by using 32a spores compared to vegetative cells. Abstract Several factors may affect the success of biocontrol agents in the field, some of which are sparsely studied. This work aimed to evaluate the influence of the inoculum type of Bacillus amyloliquefaciens subsp. plantarum 32a on the production of antibacterial metabolites, the colonization level of tomato and the control efficacy of crown gall disease. When 32a cells were grown in the optimized medium, spore inoculum yielded approximately 10 fold more anti- Agrobacterium activity than vegetative inoculum. LC-MS analysis showed that spore inoculated culture produced a pronounced shift toward shorter alkyl chains for surfactins (C13 and C14). When applied to the soil, 32a successfully colonized roots, stem and leaves of tomato. Higher population density was obtained during the treatment of soil with spores, compared to that with vegetative cells. The crown gall disease symptoms, caused by A. tumefaciens , were reduced by strain 32a at different extent depending on the inoculum type treatment. A more pronounced protection was obtained when 32a spores were used for soil inoculation. In this study, we showed for the first time that the inoculum type is one of the important factors affecting the success of a biocontrol agent. This information has significant implications in improving the efficacy of biopesticides. [ABSTRACT FROM AUTHOR]

This study investigated the individual and interactive effects of three factors - temperature, inoculum/substrate ratio (ISR) and inoculum typology - on the anaerobic digestion of corn ethanol distillery wastewater. Biochemical methane potential assays planned with factorial design with two independent quantitative variables on three levels (ISR: 1:1, 2:1 and 3:1; temperature: 30°C, 33.5°C, 37°C) and one independent qualitative variable (inoculum type: suspended, granular, mixed) have been performed. Response Surface Methodology has been used to study the effect of the factors with the aim of maximizing the specific methane yields (Y) obtainable with this substrate. The results show that all three investigated factors influence in a significant matter the Y, the ISR having the strongest effect on it. The temperature has significant influence on the Y only in combination with high ISR values. The optimal conditions for the maximum Y (551 mL CH g VS) have been found at 37°C operating temperature, ISR=3:1 and using granular inoculum. These conditions gave rise to a 4-fold increase of Y with respect to the worst combination of factors (Y=129 mL g VS for the suspended inoculum type, at 30°C and ISR=1:1). The results improve the knowledge on the digestion of this substrate, providing information for successful process up-scaling. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

A batch nitrification process was studied using synthetic wastewater as substrate and Chilean natural zeolite as biomass carrier at ambient temperatures (20 °C). Three groups of experiments were carried out: a first experimental set (I) with and without added zeolite using initial biomass concentrations of 1,000 and 2,000 mg VSS/L; a second set of experiments (II) with added zeolite and at the same initial biomass concentrations. In these two experimental sets, biomass from an activated sludge process located in an urban wastewater treatment plant at La Farfana, Santiago de Chile, was used as inoculum (1). Finally, a third set of experiments (III) was carried out with zeolite at an initial biomass concentration of 1,000 mg VSS/L using an inoculum derived from an activated sludge process treating wastewater from a paper mill (inoculum 2). Nitrifying biomass concentration values in the range of 13,000-18,800 mg VSS/L were achieved when initial biomass concentrations varied between 1,000 and 2,000 mg VSS/L. Inoculum (1) generated higher biomass concentrations than inoculum (2). Ammonium N removals higher than 70 % were obtained in experimental sets II and III when zeolite was used. For both initial biomass concentrations tested, an exponential biomass growth was observed up to the second day of operation, and a slight decrease was evident afterwards, achieving stationary values after 10-12 days of operation. The third experimental set (III) revealed that the highest N consumption took place between days 11 and 16 of digestion. [ABSTRACT FROM AUTHOR]

The article discusses research on the micropropagation and conservation of the wild medicinal orchid, Coelogyne cristata in Myanmar. The mature capsules of the orchids were taken from the Mingalardon Orchid Farm in Yangon, Myanmar. The Coelogyne cristata is generally used as a traditional medicine for dysentery and diarrhea. The study evaluates the role of plant parts and exogenous plant growth regulators in facilitating the induction of shoots.

The technical feasibility of valorizing tequila vinasse (TV), a wastewater with high pollution potential, through the production of biogenic hydrogen via dark fermentation, has long been proven in diverse lab-scale reactors that were operated either in batch or continuous mode. However, such systems have mainly been tested with diluted streams and nutrient supplementation, hindering the techno-economic attractiveness of the TV-to-hydrogen concept at large scale. In this study, the feasibility of producing hydrogen from high-strength undiluted TV with no added extra nutrients was evaluated under batch mesophilic conditions. Additionally, the use of two different acidogenic inocula obtained either by heat or heat-aeration pretreatment was investigated to get a greater understanding of the effect of inoculum type on the process. The results obtained showed that the TV utilized herein contained macro- and micro-nutrients high enough to support the hydrogenogenic activity of both cultures, entailing average hydrogen yields of 2.4–2.6 NL H2/L vinasse and maximum hydrogen production rates of 1.4–1.9 NL H2/L-d. Interestingly, the consumption of lactate and acetate with the concomitant production of butyrate was observed as the main hydrogen-producing route regardless of the inoculum, pointing out the relevance of the lactate-driven dark fermentative process. Clostridium beijerinckii was ascertained as key bacteria, but only in association with microorganisms belonging to the genera Enterobacter and Klebsiella, as revealed by phylogenetic analyses. [ABSTRACT FROM AUTHOR]

The lack of an adequate shelf-life in mycoherbicidal products has been an obstacle to their commercialization. Therefore, experiments were conducted to study the effect of inoculum type and concentration on the viability of the encapsulated propagules of Fusarium oxysporum, abbreviated as Foxy 2, in Pesta granules during storage. Pesta granules were made with different inocula of Foxy 2, including: microconidia, a mixture of mycelia and microconidia, and fresh as well as dried chlamydospore-rich biomass, each with three different inoculum concentrations. All granular preparations (0.5–2 mm, particle size) were stored at 4 °C or at room temperature (21 ± 3 °C) for 1year. All Pesta granules containing chlamydospore-inoculum retained higher viability (up to 100%) than those with mycelial and/or microconidial inocula, irrespective of inoculum concentration and storage temperature. Microconidial and mycelial preparations were not viable after 1 year at room temperature. Throughout the year, the viability of fresh and dried chlamydospore-rich biomass was not significantly affected by the concentration of chlamydospores in the formulation at 4 °C or room temperature. Thus, 85–100% viability of Foxy 2 propagules can be achieved in Pesta granules (0.5–2 mm) for at least 1 year by formulating chlamydospore-rich biomass and storing at a temperature of 4 °C. This information has significant implications in enhancing shelf-life of Foxy 2 products thereby helping us to overcome this obstacle to commercialization. [Copyright &y& Elsevier]

• Three different pH values and different inocula were investigated for PA production. • The highest propionic acid yield was achieved at pH 6 using pre-treated food and I 3. • The highest total VFA concentration of 60 g L−1 was obtained at pH 8 using pre-treated food and I 2. • VFA compositions varied based on the pH value and the substrate used. In this study, lab-scale batch fermentation tests were carried out at mesophilic temperature (30 °C) to examine the influence of inoculum type, pH-value, and thermal pretreatment of substrate on propionic acid (PA) production from dog food. The selected inocula comprised a mixed bacterial culture, milk, and soft goat cheese. The batch tests were performed at pH 4, pH 6, and pH 8 for both, untreated and thermally pretreated food. Results show that the production of PA and volatile fatty acids (VFAs) in general were significantly dependent on the chosen inoculum and adjusted pH value. The maximum PA production rates and yields were determined for the cheese inoculum at pH 6 using untreated and pretreated dog food. PA concentration reached 10 g L−1 and 26.5 g L−1, respectively. Our findings show that by selecting optimal process parameters, an efficient PA production from model food waste can be achieved. [ABSTRACT FROM AUTHOR]

In submerged fermentation of Streptomyces sp. N1 in a shake flask, glucose (3% w/v) and (NH)SO (0.6% w/v) were found to be suitable for extracellular l-glutamate oxidase (GluOx) (EC.1.4.3.11) production. GluOx production was higher with the addition of further KCl or MgCl to the medium within the range of 0 to 0.12% (w/v). The effect of inoculum type, that is, spore inoculation or mycelium inoculation on GluOx biosynthesis was also investigated, and the maximum GluOx production obtained was 2.7 U/ml after 33h fermentation with mycelium inoculation. The results demonstrated a much higher GluOx production and productivity compared with those reported previously. [ABSTRACT FROM AUTHOR]