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Waste to Bioenergy: A Sustainable Approach
Published in Jos T. Puthur, Om Parkash Dhankher, Bioenergy Crops, 2022
Monika Yadav, Gurudatta Singh, Jayant Karwadiya, Akshaya Prakash Chengatt, Delse Parekkattil Sebastian, R.N. Jadeja
Tan et al. (2018) has reported that palm oil mill effluent is a good material for the generation of bioenergy. Anaerobic decomposition of POME can result in the production of methane, water and carbon dioxide through a number of reactions like hydrolysis, acidogenesis and methanogenesis (Bitton 2005, Nwuche and Ugochi 2010). The complex molecules like lipids, carbohydrates and proteins are broken down into fatty acids, sugars and amino acids, respectively, by the enzymes of anaerobic bacteria in the hydrolysis process. Acidogenic bacteria work upon these molecules and convert these fatty acids, sugars and amino acids to organic acids in the process of acidogenesis. Acetogens convert organic acids to acetate, carbon dioxide and hydrogen. Acetoclastic methanogens use this carbon dioxide and convert it into methane (Demirel and Scherer 2008, Weiland 2010). Methane can also be produced from lipids present in POME by the action of methanogenic archaea and acetogenic bacteria (Ahmad et al. 2011). In these ways, biogas, which is a biofuel, can be produced from POME.
1 Sources
Published in Saeed Sahebdelfar, Maryam Takht Ravanchi, Ashok Kumar Nadda, 1 Chemistry, 2022
Saeed Sahebdelfar, Maryam Takht Ravanchi, Ashok Kumar Nadda
The anaerobic digestion involves four biological steps in series each with the aid of special microorganisms (Weiland, 2010): Hydrolysis. Hydrolysis of large organic molecules to simpler and soluble ones (e.g., carbohydrates to sugars and proteins to amino acids) by anaerobic bacteria.Acidogenesis. Conversion of the simple organic molecules to carbon dioxide, hydrogen, ammonia and organic acids (e.g., propionic acid) by acidogenic bacteria.Acetogenesis. Conversion of organic acids to acetic acid, along with additional hydrogen, ammonia and carbon dioxide by acetogenic bacteria.Methanogenesis. Decomposition of the acetic acid to methane and carbon dioxide by methanogenic bacteria.
Plant-microbe Interaction in Attenuation of the Toxic Waste in the Ecosystem
Published in Vivek Kumar, Rhizomicrobiome Dynamics in Bioremediation, 2021
Mary Isabella Sonali, Veena Gayathri Krishnaswamy
Anaerobic degradation takes place in the absence of oxygen and, more predominantly, when anaerobes are dominant over aerobes. Landfill biodegradation takes in the anaerobic condition through the digestion process. This is majorly used in the wastewater treatment of sludge as it reduces the large volume of input material. It reduces the risk of landfill gas getting emitted into the environment. It produces fertilizers and renewable energy such as methane and CO2, which can be utilized for the production of biogas. Bacteria hydrolyze to produce carbohydrates to utilize them as a food source. Acetogenic bacteria are a group of bacteria that can convert proteins (amino acids) into hydrogen, ammonia, carbon dioxide, and organic acid; further, it is converted into acetic acid. Methanogens are a group of bacteria that can produce methane and CO2 utilizing the products obtained from acetogenins. E. coli can take part in aerobic, anaerobic and fermentative respiration using fumarate and nitrites as electron acceptors (Sims and Kanissery 2019).
Syntrophy of bacteria and archaea in the anaerobic catabolism of hydrocarbon contaminants
Published in Critical Reviews in Environmental Science and Technology, 2023
Jean Damascene Harindintwali, Leilei Xiang, Fang Wang, Scott X. Chang, Zhiliang Zhao, Zhi Mei, Zhongjun Jia, Xin Jiang, Yong-guan Zhu, James M. Tiedje
In methanogenic environments, where there is no light and inorganic electron acceptors such as oxygen, nitrate, or sulfate, complex microbial communities use protons as electron acceptors to degrade complex organic compounds to a series of products. First, a diverse range of primary degrading microorganisms, including anaerobic bacteria, fungi, and protozoa, decompose complex organic compounds to methanogenic substrates (e.g., H2, CO2, acetate, and/or formate) and/or intermediate metabolites, such as short-chain volatile fatty acids (e.g., propionate and butyrate) and alcohols (e.g., ethanol, isopropanol, and butanol). Acetogenic bacteria then decompose the intermediate metabolites into H2, CO2, acetate, and/or formate, which can then be consumed by methanogens, resulting in the production of methane, protons, and electrons (Lie et al., 2012). Volatile fatty acids are among the most common intermediate metabolites in anaerobic digestion, which may constitute the major source of the methane produced during microbial methanogenesis (de Bok et al., 2004; Dong & Stams, 1995).
Performance assessment of compression ignition engines powered by biogas, biodiesel, and producer gas mix derived from agriculture waste
Published in Biofuels, 2023
P. Kumar, P. M. V. Subbarao, V. K. Vijay, S. A. Khan, Amit Sharma, L. D. Kala
Digestion of anaerobic is a well-known process used for biogas processing using various organic wastes. It is a biochemical breakdown procedure in which microorganisms accumulate in an anaerobic condition and produces biogas. The process of anaerobic digestion is complex and may be broken down into four distinct stages as shown in Figure 1. The first step of the reaction begins with hydrolysis, then moves on to acidogenesis, acetogenesis, and methanogenesis. Hydrolysis is the first step, where complex organic molecules like proteins, starches, fats, etc., are broken down into single-chain monomers with the help of enzymes. The second phase of the process is called acedogenesis. At this step, volatile fatty acids, carbon dioxide, and hydrogen sulphide production takes place with the aid of acedogenic bacteria. The third stage of the process is known as acetogenesis, in which acetogens bacteria transform simple monomers formed during the acedogenesis into acetic acid, acetate, carbon dioxide, and hydrogen. Methanogenic bacteria convert all the byproducts formed in the earlier stages of the anaerobic process into CH4, CO2, and water.
Utilizing bioaugmentation to improve performance of a two-phase AnMBR treating sewage sludge
Published in Environmental Technology, 2020
Ana D. Martin-Ryals, Lance C. Schideman, Matthew Ong
In addition to hydrolytic bacteria, bioaugmentation with acetic acid producing bacteria or acetogens could also benefit system performance. Acetate is a key substrate for methanogenesis with approximately 70% of methane being produced from the reduction of acetate [29]. In anaerobic treatment, acetate is produced by either acetic acid producing bacteria though fermentation of soluble intermediates, or by acetogens via anaerobic oxidation of volatile fatty acids (VFA) or the reduction of CO2 with H2 [29–31]. Accumulation of VFA can be detrimental to anaerobic processes due to the associated decrease in pH, which can inhibit methanogenesis [32]. Thus, bioaugmentation with acetogens and acetic acid producing bacteria could benefit process performance by both increasing the availability of acetate for methanogenesis and by reducing the accumulation of other VFA intermediates that could lead to process inhibition.