scholarly journals Organic waste conversion through anaerobic digestion: A critical insight into the metabolic pathways and microbial interactions

Author(s):  
Monika Yadav ◽  
Chandrakant Joshi ◽  
Kunwar Paritosh ◽  
Jyotika Thakur ◽  
Nidhi Pareek ◽  
...  
2021 ◽  
Vol 24 (1) ◽  
pp. 8-13
Author(s):  
Darwin ◽  
Atmadian Pratama ◽  
Mardhotillah

AbstractAnaerobic co-digestion of oil palm empty fruit bunches with cow manure was studied. The research focus was on the evaluation of feeding different solid concentrations of the substrate in the on-going process of anaerobic digestion. The solid concentrations ranged from 0.5 to 12% TS. Results of the study showed that the maximum methane production could be reached with the reactor digesting substrates with 4 to 8% TS, in which the methane produced was from 1300 to 1400 mL per day. A significant drop of pH from 7.02 to 5.97 occurred when the reactor was digesting substrates with 10 and 12% TS. Acidic condition caused by organic matter overloads lowered the efficiency of organic conversion represented in the low removal of COD, which was only 22.4%. This finding is highly significant for the waste management industries in terms of dealing with the digester upset due to the digestion of large amount of organic wastes.


2007 ◽  
pp. 291-296
Author(s):  
Sunil Kumar ◽  
Somnath Mukherjee ◽  
Sukumar Devotta

Anaerobic digestion (AD) is viewed as an attractive method for waste stabilization prior tolandfills as pre-treatment to reduce significant pollution load to the environment Optimizinganaerobic digestion process aims to maximize organic waste conversion to biogas at shortdigestion period, The optimization of high solid concentration of MSW in a laboratory scalereactor was carried out to know the maximum biogas production yield,This paper presents the findings of the study on high solid AD process in single whichinvolves enhanced pre-stage (hydrolysis and acidification) and methane phase,


2016 ◽  
Vol 83 (2) ◽  
Author(s):  
Live H. Hagen ◽  
Jeremy A. Frank ◽  
Mirzaman Zamanzadeh ◽  
Vincent G. H. Eijsink ◽  
Phillip B. Pope ◽  
...  

ABSTRACT In this study, we used multiple meta-omic approaches to characterize the microbial community and the active metabolic pathways of a stable industrial biogas reactor with food waste as the dominant feedstock, operating at thermophilic temperatures (60°C) and elevated levels of free ammonia (367 mg/liter NH3-N). The microbial community was strongly dominated (76% of all 16S rRNA amplicon sequences) by populations closely related to the proteolytic bacterium Coprothermobacter proteolyticus. Multiple Coprothermobacter-affiliated strains were detected, introducing an additional level of complexity seldom explored in biogas studies. Genome reconstructions provided metabolic insight into the microbes that performed biomass deconstruction and fermentation, including the deeply branching phyla Dictyoglomi and Planctomycetes and the candidate phylum “Atribacteria.” These biomass degraders were complemented by a synergistic network of microorganisms that convert key fermentation intermediates (fatty acids) via syntrophic interactions with hydrogenotrophic methanogens to ultimately produce methane. Interpretation of the proteomics data also suggested activity of a Methanosaeta phylotype acclimatized to high ammonia levels. In particular, we report multiple novel phylotypes proposed as syntrophic acetate oxidizers, which also exert expression of enzymes needed for both the Wood-Ljungdahl pathway and β-oxidation of fatty acids to acetyl coenzyme A. Such an arrangement differs from known syntrophic oxidizing bacteria and presents an interesting hypothesis for future studies. Collectively, these findings provide increased insight into active metabolic roles of uncultured phylotypes and presents new synergistic relationships, both of which may contribute to the stability of the biogas reactor. IMPORTANCE Biogas production through anaerobic digestion of organic waste provides an attractive source of renewable energy and a sustainable waste management strategy. A comprehensive understanding of the microbial community that drives anaerobic digesters is essential to ensure stable and efficient energy production. Here, we characterize the intricate microbial networks and metabolic pathways in a thermophilic biogas reactor. We discuss the impact of frequently encountered microbial populations as well as the metabolism of newly discovered novel phylotypes that seem to play distinct roles within key microbial stages of anaerobic digestion in this stable high-temperature system. In particular, we draft a metabolic scenario whereby multiple uncultured syntrophic acetate-oxidizing bacteria are capable of syntrophically oxidizing acetate as well as longer-chain fatty acids (via the β-oxidation and Wood-Ljundahl pathways) to hydrogen and carbon dioxide, which methanogens subsequently convert to methane.


2021 ◽  
Vol 9 (1) ◽  
pp. 190
Author(s):  
Yuqi Li ◽  
Zhenxiang Meng ◽  
Yao Xu ◽  
Qicheng Shi ◽  
Yuping Ma ◽  
...  

Anaerobic fungi in the digestive tract of herbivores are one of the critical types of fiber-degrading microorganisms present in the rumen. They degrade lignocellulosic materials using unique rhizoid structures and a diverse range of fiber-degrading enzymes, producing metabolic products such as H2/CO2, formate, lactate, acetate, and ethanol. Methanogens in the rumen utilize some of these products (e.g., H2 and formate) to produce methane. An investigation of the interactions between anaerobic fungi and methanogens is helpful as it provides valuable insight into the microbial interactions within the rumen. During the last few decades, research has demonstrated that anaerobic fungi stimulate the growth of methanogens and maintain methanogenic diversity. Meanwhile, methanogens increase the fiber-degrading capability of anaerobic fungi and stimulate metabolic pathways in the fungal hydrogenosome. The ability of co-cultures of anaerobic fungi and methanogens to degrade fiber and produce methane could potentially be a valuable method for the degradation of lignocellulosic materials and methane production.


Author(s):  
Hannah Lee

This paper is the attempt to show how system theory could provide critical insight into the transdisciplinary field of library and information sciences (LIS). It begins with a discussion on the categorization of library and information sciences as an academic and professional field (or rather, the lack of evidence on the subject) and what is exactly meant by system theory, drawing upon the general system theory established by Ludwig von Bertalanffy. The main conversation of this paper focuses on the inadequacies of current meta-level discussions of LIS and the benefits of general system theory (particularly when considering the exponential rapidity in which information travels) with LIS.


2012 ◽  
Vol 48 (1) ◽  
pp. 23-27
Author(s):  
TOMONAO MIYASHIRO ◽  
QINGHONG WANG ◽  
YINGNAN YANG ◽  
KAZUYA SHIMIZU ◽  
NORIO SUGIURA ◽  
...  

2018 ◽  
Vol 1 (1) ◽  
pp. 18
Author(s):  
Kym Maclaren

“To consent to love or be loved,” said Merleau-Ponty, “is to consent also to influence someone else, to decide to a certain extent on behalf of the other.” This essay explicates that idea through a meditation on intimacy. I propose, first, that, on Merleau-Ponty’s account, we are always transgressing into each other’s experience, whether we are strangers or familiars; I call this “ontological intimacy.” Concrete experiences of intimacy are based upon this ontological intimacy, and can take place at two levels: (1) at-this-moment (such that we can experience intimacy even with strangers, by sharing a momentary but extra-ordinary mutual recognition) and (2) in shared interpersonal institutions, or habitual, enduring, and co-enacted visions of who we are, how to live, and what matters. Through particular examples of dynamics within these layers of intimacy (drawing upon work by Berne and by Russon), I claim that we are always, inevitably, imposing an “unfreedom” upon our intimate others. Freedom, then, can only develop from within and by virtue of this “unfreedom.” Thus, what distinguishes empowering or emancipating relationships from oppressive ones is not the removal of transgressive normative social forces; it is rather the particular character of those transgressive forces. Some transgressions upon others’ experience—some forms of “unfreedom”—will tend to promote freedom; others will tend to hinder it. This amounts to a call for promoting agency and freedom not only through critical analysis of public institutions, practices and discourses, but also through critical insight into and transformation of our most private and intimate relationships.


Coronaviruses ◽  
2020 ◽  
Vol 1 (1) ◽  
pp. 49-56
Author(s):  
Gaurav M. Doshi ◽  
Hemen S. Ved ◽  
Ami P. Thakkar

The World Health Organization (WHO) has recently announced the spread of novel coronavirus (nCoV) globally and has declared it a pandemic. The probable source of transmission of the virus, which is from animal to human and human to human contact, has been established. As per the statistics reported by the WHO on 11th April 2020, data has shown that more than sixteen lakh confirmed cases have been identified globally. The reported cases related to nCoV in India have been rising substantially. The review article discusses the characteristics of nCoV in detail with the probability of potentially effective old drugs that may inhibit the virus. The research may further emphasize and draw the attention of the world towards the development of an effective vaccine as well as alternative therapies. Moreover, the article will help to bridge the gap between the new researchers since it’s the current thrust area of research.


2020 ◽  
Vol 67 (1) ◽  
pp. 148-155
Author(s):  
Anatoliy V. Fedotov ◽  
Viktor S. Grigoriev ◽  
Dmitriy A. Kovalev ◽  
Andrey A. Kovalev

To speed up the wastewater treatment under aerobic conditions and to optimize the processes of anaerobic wastewater treatment in digesters, immobilization technologies of microorganisms and enzymes on solid carriers are used. Ceramic carriers based on aluminosilicates and alumina are one of the promising inorganic biomass carriers. (Research purpose) To study the structure of porous ceramic biomass carriers for anaerobic processing of organic waste and evaluate the prospects for their use. (Materials and methods) The substrate for anaerobic digestion was a mixture of sediments of the primary and secondary sewage sumps of the Lyubertsy treatment facilities. K-65 cattle feed was used to ensure the constancy of the composition of organic substances in substrates as a cosubstrate. The authors used the method of low-temperature nitrogen adsorption of Bruner-Emmett-Teller to study the pore structure and specific surface of solid carriers on a specific surface analyzer Quntachrome Autosorb-1. (Results and discussion) The main characteristics (specific surface, volume of micro- and mesopores, predominant pore radius, water absorption and others) of chamotte foam lightweight and highly porous corundum ceramics were determined. It was revealed that ceramic materials with a developed surface and electrically conductive material provided an increase in biogas yield by 3.8-3.9 percent with an increase in methane content by an average of 5 percent. (Conclusions) The results of anaerobic digestion showed a positive effect of both a conductive carrier and highly porous ceramic materials on the process of anaerobic bioconversion of organic waste into biogas. It is advisable to expand experimental studies on the use of a conductive carrier with a developed surface based on highly porous ceramics.


Sign in / Sign up

Export Citation Format

Share Document