Low-cost additive improved silage quality and anaerobic digestion performance of napiergrass

Bioaugmentation potential of inoculum derived from anaerobic digestion feedstock for enhanced methane production using water hyacinth

The utilisation of water hyacinth for production of biogas is considered to be a solution to both its control and the global renewable energy challenge. In this instance, an investigation was conducted to evaluate the potential of water hyacinth inoculum to enhance methane production during anaerobic digestion (AD). Chopped whole water hyacinth (10% (w/v)) was digested to prepare an inoculum consisting mainly of water hyacinth indigenous microbes. The inoculum was incorporated in the AD of freshly chopped whole water hyacinth to set up different ratios of water hyacinth inoculum and water hyacinth mixture with appropriate controls. The results of batch tests with water hyacinth inoculum showed a maximal cumulative volume of 211.67 ml of methane after 29 days of AD as opposed to 88.6 ml of methane generated from the control treatment without inoculum. In addition to improving methane production, inclusion of water hyacinth inoculum reduced the electrical conductivity (EC) values of the resultant digestate, and, amplification of nifH and phoD genes in the digestate accentuates it as a potential soil ameliorant. This study provides an insight into the potential of water hyacinth inoculum to enhance methane production and contribute to the feasibility of the digestate as a soil fertility enhancer.

Characterization of Enterococcus faecalis JF85 and Enterococcus faecium Y83 isolated from Tibetan yak (Bos grunniens) for ensiling Pennisetum sinese

Two bacteria strains with cellulolytic potential isolated from Tibetan yak (Bos grunniens) rumen were identified as Enterococcus faecalis (JF85) and Enterococcus faecium (Y83). Isolates grow well within a range of temperature 15 to 55 °C and pH 3.0-7.0, respectively. Two strains were inoculated with or without Lactobacillus plantarum (Lp) to Pennisetum sinese silage for 90 days. All inoculants increased lactic acid content, decreased pH and lignocellulose contents compared with silage without additives (control). The lowest pH, highest lactic acid and largest reduction in lignocellulose contents were observed in JF85+Lp and Y83+Lp silages. Isolates alone or in combination with Lp significantly increased WSC, mono- and disaccharides contents as compared to the control. Combined addition efficiently improved enzymatic hydrolysis of Pennisetum sinese silage, indicated by higher glucose yield and cellulose convertibility. Pennisetum sinese ensiled with combined additives is a suitable storage and pretreatment method prior to sugars production from energy crop.

Hydrolysis dynamics for batch anaerobic digestion of elephant grass

Elephant grass might be a potential source of fine chemical precursors and bioenergy.

Effect of microalgae supplementation on the silage quality and anaerobic digestion performance of Manyflower silvergrass

The silage quality of Manyflower silvergrass with microalgae supplementation was investigated, and the variation in bacterial communities during ensilage period was analyzed by high-throughput sequencing technology. In addition, the specific methane yields of the silages were also evaluated. Results showed that the samples with microalgae supplementation have lower pH value and higher lactic acid concentration (8.0 mg/g FM). Meanwhile, higher NH3-N concentration was observed since microalgae were N-rich material. Microalgae additions also influenced the bacterial community structure. For the samples without microalgae, the major genus was Enterococcus from day 1 to day 3, and then Lactobacillus became the dominant genus. While the prevalent genus represented in the samples with microalgae supplementation was Lactobacillus. The specific methane yields of all samples were within the range of 153 ± 1 mL/g VS to 178 ± 11 mL/g VS and no significant difference was observed.