scholarly journals Polyhydroxyalkanoated-Rich Microbial Cells from Bio-Based Volatile Fatty Acids as Potential Ingredient for Aquaculture Feed

Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 38
Author(s):  
Alice Botturi ◽  
Federico Battista ◽  
Marco Andreolli ◽  
Filippo Faccenda ◽  
Salvatore Fusco ◽  
...  

In this study, the production of polyhydroxyalkanoated PHA-rich microbial biomass as a novel feed additive in aquaculture was investigated at a lab-scale. Bio-based volatile fatty acids (VFAs), obtained from the acidogenic fermentation of agricultural residues in existing anaerobic digestion plants, were used as carbon and energy to cultivate the PHA-rich microbial biomass. The experimental activities were carried out using Thauera sp. Sel9 as pure strain, which was grown in a continuous stirred-tank reactor (CSTR) operated at three different hydraulic retention times (HRT). The highest productivity obtained of biomass cells was 0.69 g/L day, operating at one day HRT while the observed PHAs production yield was 0.14 gPHA/g soluble COD removed. At these conditions, the PHA concentration in the microbial cells was 41%. Although the sulfur amino acids were available at high concentrations and above the typical concentration found in fishmeal, the amino acids profile of the obtained biomass revealed a lack of histidine and threonine. A preliminary economic analysis showed that the production of a novel source of feed additive from the conversion of agro-residues could give higher benefits in terms of revenues compared to the production of biogas production through anaerobic digestion.

2018 ◽  
Vol 49 (2) ◽  
pp. 130-137
Author(s):  
Demetrio Antonio Zema ◽  
Giovanni Zappia ◽  
Souraya Benalia ◽  
Giuseppe Zimbalatti ◽  
Enzo Perri ◽  
...  

Experimental trials of anaerobic digestion of olive mill wastewater (OMW) blended with other agro-industrial by-products were carried out to evaluate biogas production and sensitivity of the process to inhibiting compounds. Blends containing different percentages of OMW, digested liquid manure, and citrus peel were subjected to a batch anaerobic digestion process under both mesophilic and thermophilic conditions. The results showed that blends with percentages of OMW higher than 20% (v/v) had low methane yields due high concentrations of polyphenols (PPs) and/or volatile fatty acids (concentrations above 0.8 g kg–1 and 2.4 g L–1, respectively). The addition of other substrates such as citrus peel may have induced synergic inhibiting effects of PPs and essential oils (EO) on microbial growth. Thermophilic processes were more sensitive to these inhibiting compounds than mesophilic processes. The results of this study suggest that reducing PPs and EO concentrations in blends subject to anaerobic digestion below the inhibiting concentrations of 0.6 g L–1 and 0.5 g kg–1, respectively, is suitable. Additionally, it is advisable to maintain the volatile fatty acids content below 2 g L–1 to avoid its evident toxic effects on the growth of microorganisms in biochemical processes.


2011 ◽  
Vol 356-360 ◽  
pp. 2510-2514 ◽  
Author(s):  
Ming Fen Niu ◽  
Sai Yue Wang ◽  
Wen Di Xu ◽  
An Dong Ge ◽  
Hao Wang

In order to improve the rate of degradation of cellulose in corn straw, the study has an important significance that compost corn straw with inoculating high-efficient microbe agents. The experiment inoculated a cellulose-degrading strain F2 which was screened from compost into compost pretreatment, the VS of corn straw reduced from 93.14% to 71.69% after 15 days, the content of cellulose reduced from 34.12g·kg-1 to 25.66g·kg-1, the rate of degradation was 24.79% which was 10.60% higher than those without the strain. An anaerobic fermentation experiment was carried out with the two groups of composted corn straw and mixed pig feces with a certain ratio, and investigations of biogas production, pH, content of volatile fatty acids(VFA) and rate of methane production were conducted. The results were that the corn straw composted with the cellulose-degrading strain peaked 4 days earlier, the maximal daily biogas production was 1470mL, the cumulative biogas production reached 23641mL which was 16.87% higher and operated stably earlier. The study showed that the cellulose-degrading strain had a strong capacity to degrade cellulose in corn straw, and then improved the performance of anaerobic digestion.


2008 ◽  
Vol 58 (7) ◽  
pp. 1521-1528 ◽  
Author(s):  
H. B. Nielsen ◽  
I. Angelidaki

The present study focuses on process imbalances in Danish centralized biogas plants treating manure in combination with industrial waste. Collection of process data from various full-scale plants along with a number of interviews showed that imbalances occur frequently. High concentrations of ammonia or long chain fatty acids is in most cases expected to be the cause of microbial inhibitions/imbalances while foaming in the prestorage tanks and digesters is the most important practical process problem at the plants. A correlation between increased residual biogas production (suboptimal process conditions) and high fractions of industrial waste in the feedstock was also observed. The process imbalances and suboptimal conditions are mainly allowed to occur due to 1) inadequate knowledge about the waste composition, 2) inadequate knowledge about the waste degradation characteristics, 3) inadequate process surveillance, especially with regard to volatile fatty acids, and 4) insufficient pre-storage capacity causing inexpedient mixing and hindering exact dosing of the different waste products.


2002 ◽  
Vol 45 (10) ◽  
pp. 65-73 ◽  
Author(s):  
D.J. Batstone ◽  
J. Keller ◽  
I. Angelidaki ◽  
S.V. Kalyuzhnyi ◽  
S.G. Pavlostathis ◽  
...  

The IWA Anaerobic Digestion Modelling Task Group was established in 1997 at the 8th World Congress on Anaerobic Digestion (Sendai, Japan) with the goal of developing a generalised anaerobic digestion model. The structured model includes multiple steps describing biochemical as well as physico-chemical processes. The biochemical steps include disintegration from homogeneous particulates to carbohydrates, proteins and lipids; extracellular hydrolysis of these particulate substrates to sugars, amino acids, and long chain fatty acids (LCFA), respectively; acidogenesis from sugars and amino acids to volatile fatty acids (VFAs) and hydrogen; acetogenesis of LCFA and VFAs to acetate; and separate methanogenesis steps from acetate and hydrogen/CO2. The physico-chemical equations describe ion association and dissociation, and gas-liquid transfer. Implemented as a differential and algebraic equation (DAE) set, there are 26 dynamic state concentration variables, and 8 implicit algebraic variables per reactor vessel or element. Implemented as differential equations (DE) only, there are 32 dynamic concentration state variables.


2009 ◽  
Vol 60 (2) ◽  
pp. 339-346 ◽  
Author(s):  
H. Fabian Jacobi ◽  
Christian R. Moschner ◽  
Eberhard Hartung

Recently biogas production from agricultural sources has rapidly developed. Therefore the demands on biogas plants to optimise the efficiency of the anaerobic digestion (AD) process have grown immensely. At present there is no online-supervision tool available to monitor the AD process, but costly and time-consuming chemical analyses are necessary. The possibility to use near-infrared spectroscopy (NIRS) in order to track relevant process parameters like total volatile fatty acids (VFA), acetic acid and propionic acid was investigated in the present research project. A NIR-sensor was integrated into a full-scale 1 MW biogas plant and NIR-spectra of the fermenter contents were recorded semi-continuously for 500 days. Weekly samples were taken and analysed for the above mentioned parameters. Calibration models were calculated, capable of following these parameters: VFA (r2=0.94), acetic acid (r2=0.69), propionic acid (r2=0.89).


2014 ◽  
Vol 34 (11) ◽  
pp. 2080-2089 ◽  
Author(s):  
Ingrid H. Franke-Whittle ◽  
Andreas Walter ◽  
Christian Ebner ◽  
Heribert Insam

2007 ◽  
Vol 15 (2) ◽  
pp. 123-135 ◽  
Author(s):  
Jens Bo Holm-Nielsen ◽  
Helga Andree ◽  
Harald Lindorfer ◽  
Kim H. Esbensen

This work reports an off-line method development simulating at-line anaerobic co-digestion process monitoring using a new transflexive embedded near infrared sensor (TENIRS) system as a process analytical chemistry (PAC) facility. The operative focus is on optimising anaerobic digestion biogas production with energy crops as the main feedstock. Results show that several key monitoring intermediates in the anaerobic fermentation process can be quantified directly using near infrared spectroscopy with good results, especially ammonium and total volatile fatty acids. Good feasibility study prediction validations have been obtained for total solids (TS), volatile solids (VS), ammonium, acetic acid and total volatile fatty acids. The TENIRS system is a new option for real-time, at-line/on-line monitoring of biogas fermentation operations, offering a robust, low-budget PAC approach to a rapidly growing bulk volume industry.


Author(s):  
Zangta Sang ◽  
Chayanon Sawatdeenarunat ◽  
Pitchaya Suaisom

Anaerobic digestion (AD) of starch wastewater for biogas production has been widely installed in Thailand for a decade. Unfortunately, this specific waste stream contains low alkalinity (Alk) and high volatile fatty acids (VFAs) which could easily lead to system instability. The appropriate monitoring indicators could help to decrease chance of reactor failure. The aim of this study is to investigate the performance of the AD system and the effect of operating parameters i.e. oxidation-reduction potential (ORP) and pH on the system in a continuous stirred tank reactor operated in semi-continuous mode at organic loading rate (OLR) of 1.0 kg COD/m3.day.  The temperature was controlled at a mesophilic condition (35±2°C) for the whole experiment. The results showed that the average ORP and pH were -400 ±50 mV and 7.0 ± 0.2, respectively. The average biogas and methane yields were 0.901±0.128 NL/g VS added and 0.528±0.076 NL/g VS added, respectively.  The methane composition was 58.43±4.76 %. The total COD and filtrated COD removal efficiencies were   94.75±1.42% and 97.88±0.53%, respectively. It could be concluded that at the low OLR (i.e. 1.0 kg COD/m3.day), pH and ORP was stable and fell within the recommended range for AD and indicated the stability of the system.


2021 ◽  
Vol 48 (3) ◽  
pp. 193-203
Author(s):  
R. Y. Aderinboye ◽  
A. O. Olanipekun

The potential risk to animal and human health in the use of antibiotic feed additives for modifying rumen fermentation has necessitated the search for natural alternatives which are generally regarded as safe. The aim of this study was to evaluate the potentials of turmeric powder in rumen manipulation using the in vitro method. Substrate of Panicum maximum and concentrate in ratio 6: 4 with turmeric inclusion at four levels of 0, 5, 10 and 15 mg/g dry matter (DM) were used for this study. The experiment was arranged in a completely randomized design. Approximately 200 mg of substrate in each treatment was weighed separately into 100 mL glass syringes into which 30 mL of rumen fluid and buffer solution (1:2 v/v) were added. The quantities of total gas, methane, ammonia, total volatile fatty acids production and substrate degraded were determined 48-h post incubation. Rumen bacteria, protozoa, fungi population were determined and microbial biomass was estimated. Some phytochemical constituents of turmeric were also determined using standard methods. Turmeric had a higher percentage of curcumin relative to other phytochemical contents determined. Turmeric effectively and consistently (p < 0.05) reduced gas production at levels above 5 mg/g of substrate inclusion throughout the 48-h incubation period. Similarly, turmeric reduced (p < 0.05) methane, carbon-dioxide, ammonia and total volatile fatty acids production, and substrate degradation at 10 – 15 mg/g inclusion. Rumen bacteria and protozoa reduced when turmeric was included at 10 – 15 mg/g while fungi reduction was observed at 15 mg/g of inclusion. Reduction in microbial biomass was observed at 15 mg/g of turmeric inclusion. It can be concluded from this study that turmeric inclusion above 5 mg/g DM of substrate, can modify the rumen by causing a reduction in fermentation end-products. The reduction of ammonia production at 15 mg/g which significantly reduced microbial biomass has implication for lowering microbial protein synthesis.     Le risque potentiel pour la santé animale et humaine dans l'utilisation d'additifs alimentaires antibiotiques pour modifier la fermentation du rumen a nécessité la recherche d'alternatives naturelles qui sont généralement considérées comme sûres. Le but de cette étude était d'évaluer les potentiels de la poudre de curcuma dans la manipulation du rumen en utilisant la méthode in vitro. Substrat de Panicum maximum et concentré dans le rapport 6: 4 avec l'inclusion de curcuma à quatre niveaux de 0, 5, 10 et 15 mg/g de matière sèche (DM) ont été utilisés pour cette étude. L'expérience a été organisée dans une conception complètement randomisée. Environ 200 mg de substrat dans chaque traitement ont été pesés séparément dans des seringues en verre de 100 mL dans lesquelles 30 mL de liquide rumen et de solution tampon (1:2 v/v) ont été ajoutés. Les quantités totales de gaz, de méthane, d'ammoniac, de production totale d'acides gras volatils et de substrat dégradé ont été déterminées 48 h après incubation. La bactérie Rumen, le protozoaire, la population de champignons ont été déterminés et la biomasse microbienne a été estimée. Certains constituants phytochimiques du curcuma ont également été déterminés à l'aide de méthodes standard. Le curcuma avait un pourcentage plus élevé de curcumine par rapport à d'autres contenus phytochimiques déterminés. Le curcuma a réduit efficacement et systématiquement (p < 0,05) la production de gaz à des niveaux supérieurs à 5 mg/g d'inclusion du substrat tout au long de la période d'incubation de 48 h. De même, le curcuma a réduit (p < 0,05) le méthane, le dioxyde de carbone, l'ammoniac et la production totale d'acides gras volatils, et la dégradation du substrat à 10 à 15 mg/g d'inclusion. Les bactéries rumen et le protozoaire ont diminué lorsque le curcuma a été inclus à 10 – 15 mg/g tandis que la réduction des champignons a été observée à 15 mg/g d'inclusion. La réduction de la biomasse microbienne a été observée à 15 mg/g d'inclusion de curcuma. On peut conclure de cette étude que l'inclusion de curcuma au- dessus de 5 mg/g de DM de substrat, peut modifier le rumen en causant une réduction des produits finaux de fermentation. La réduction de la production d'ammoniac à 15 mg/g, ce qui a considérablement réduit la biomasse microbienne, a des répercussions sur l'abaissement de la synthèse des protéines microbiennes.    


2021 ◽  
Vol 9 (2) ◽  
pp. 105055
Author(s):  
Yasmim Arantes da Fonseca ◽  
Nayara Clarisse Soares Silva ◽  
Adonai Bruneli de Camargos ◽  
Silvana de Queiroz Silva ◽  
Hector Javier Luna Wandurraga ◽  
...  

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