Biogas Produced By Fresh Ginger Stalks And Its Biogas Slurry Resource Recycling Potential And Microbiological Aspects During Methane Fermentation

Recycle agriculture is the most important content of the modern agriculture. China is one of the largest ginger cultivating country', and a large amount of ginger stalks are produced per year. Biogas fermentation is a key process to use ginger stalks effectively. This paper focus on the biogas fermentation under the condition of 25 ? using ginger stalks as raw material, and the biogas production, the gas components, the nutrient content of biogas slurry, and the cellulose, hemicellulose. and lignin content in ginger stalks was measured during the fermentation process, respectively. At the same time PCR-DGGE and representative stripe cloning sequencing and ?umina Miseq sequencing technology was used to reveal microbial communities at different stages of the ginger stalks biogas fermentation process. The results for ginger stalks actual application of biogas fermentation provide scientific guidance, and can realize the multilevel recycling of biomass energy. The conclusion is as follows:1. The gas production process of biogas fermentation could be divided into two phases at room temperature when 10% fresh ginger straw was added. The first stage of gas production began from 6d and finished at 42d; the second stage began from 63d and then finished at 121d. The average gas production rate of the whole gas production process was 803 mL/g TS. During the fermentation process, the pH was maintained in the normal range, and the highest methane content of biogas was 55.6%, which conformed to the state biogas project operation and management regulations.2. The contents of ginger straw cellulose, hemicellulose and lignin were analysed at different biogas fermentation period. The results showed that the contents the ginger straw cellulose, hemicellulose and lignin of fresh ginger Straw was 32.96%,22.03% and 7.5%, respectively. Until the end of fermentation, the contents of ginger straw-cellulose, hemicellulose and lignin of the biogas residues was 13.76%,8.06% and 58.58%, respectively; the contents of ginger straw cellulose, hemicellulose decreased, but the lignin content was increased compared with the origin.3. The PCR-DGGE technique was used to analyze the bacterial community diversity in different periods of ginger straw biogas fermentation.36 representative DGGE bands were selected for cloning and sequencing. The results indicated that the bacterial species in ginger straw biogas fermentation process were closed to the marine benthic bacteria, anaerobic bacteria in the marine environment and bacteria in cereal anaerobic digestion biogas.4. The ?umina Miseq sequencing technique was used to analyse the community diversity of bacteria and archaeain of biogas slurry samples in different fermentation periods. When analyzed the bacterial populations of three biogas slurry samples, 24833,29068 and 26557 sequences were obtained. At the 97% similarity level, there were 6692 OTUs, and among them, there were 601 OTUs for samples S1, S2 and S3. There were about 992,769 and 1141 common OTUs between S1 and S2, S1 and S3, S2 and S3, respectively. At the class level, the preponderant bacteria of S1 were Bacteroidia(24.12%), Clostridia(20.59%) and Beta proteobacteria(15.13%); the dominant bacteria of S2 were Bacteroidia(46.89%), Clostridia(21.41%) and Epsilon proteobacteria(13.5%); The main bacteria of S3 were Bacteroidia (67.73%) and Clostridia (16.2%).There were 47119,55952 and 54375 sequences obtained when sequencing the archaeain communities of three biogas slurry samples. Results showed that at the 97% similarity level, there were 3820 OTUs, and in which, there were 822 common OTUs for samples S1, S2 and S3. The same OTUs shared by S1 and S2, S1 and S3, S2 and S3 was 1042,991 and 1165, respectively. At level of the genus, the preponderant bacteria of S1 were almost non-classified archaeain; the dominant bacteria of S2 were Methanoculleus(97.93%), Methanocorpusculum(4.33%), Methanobacterium(4.06%); the main bacteria of S3 were Methanoculleus (3.21%) and Methanobacterium (2.42%).5. The differences for height and weight of fresh ginger among the three treatments were striking. Among them, the treatment combined with fertilizer and biogas slurry achieved the best results, the height of ginger was the maximum (133 ±10.44 cm) and the weight of ginger also reached the heaviest (71±1.31g). In comparison to apply chemical fertilizer, the height of ginger reached an increase of 52.8%, and the weight of fresh ginger increased 18.3% in the treatment combined with fertilizer and biogas slurry, the differences were significant.