scholarly journals Bioconversion of lignin and methane production from Corn cobs (Zea mays) treated by lignin-degrading bacteria

2021 ◽  
Vol 924 (1) ◽  
pp. 012072
Author(s):  
I Nurika ◽  
A Rahmadhanti ◽  
S Suhartini
Keyword(s):  
Methane Production ◽  
Lignin Content ◽  
Treatment Needs ◽  
Lysinibacillus Sphaericus ◽  
Corn Cobs ◽  
Degrading Bacteria ◽  
Paenibacillus Sp ◽  
Soluble Phenols ◽  
Methane Potential ◽  
Pre Treatment

Abstract Corn cobs are one of the potential feedstocks consisting of cellulose, hemicellulose and lignin, which provide potential lignocellulose biomass to be converted into renewable energy such as biogas through anaerobic digestion (AD). However, the recalcitrant structure of corn cobs lignocellulose makes it resistant to microbial access to the cell wall, and therefore the effective pre-treatment needs to be conducted. The biological pre-treatment using lignin-degrading bacteria is one of the promising bioconversion processes which will help to break down the lignocellulose structure. This study aims to analyse the ability of bacteria, Agrobacterium sp., Lysinibacillus sphaericus and Paenibacillus sp. in degrading lignin of corn cobs and therefore will enhance the methane released from AD. The ability of bacteria to degrade lignin was observed by analysis of total reducing sugar, total soluble phenols, lignin content, and weight loss, while the methane production was determined by the biochemical methane potential (BMP). The percentage of lignin content of untreated and pre-treated corn cobs with bacteria Agrobacterium sp., L. sphaericus and Paenibacillus sp. is 18.34%; 9.66%; 11.48% and 9.06%, respectively. The methane concentration (specific methane production) produced by using inoculum of Agrobacterium sp., L. sphaericus and Paenibacillus sp. with the addition of pre-treated corn cobs are 1.79%; 1.16% and 2.51%, respectively. These results were higher than the inoculum with the addition of untreated corn cobs.

scholarly journals Innovative Hydrodynamic Disintegrator Adjusted to Agricultural Substrates Pre-treatment Aimed at Methane Production Intensification—CFD Modelling and Batch Tests

Energies ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 4256 ◽  
Author(s):  
Monika Zubrowska-Sudol ◽  
Aleksandra Dzido ◽  
Agnieszka Garlicka ◽  
Piotr Krawczyk ◽  
Michał Stępień ◽  
...  
Keyword(s):  
Methane Production ◽  
Damage Zone ◽  
Positive Energy ◽  
Net Energy ◽  
Maize Silage ◽  
Cfd Modelling ◽  
Study Objective ◽  
Testing Procedures ◽  
Methane Potential ◽  
Pre Treatment

The study objective was to adjust the hydrodynamic disintegrator dedicated to sewage sludge pre-treatment (HDS) to work with agricultural substrate. This involved the development and implementation of a mathematical model of flow via the device’s domain. An innovative disintegrator (HAD—hydrodynamic disintegrator for agriculture) was designed, built, and tested based on the obtained results. The main improvements to the HDS include the implementation of shredding knives in order to overcome clogging by crushed substrate, and the application of ribs in the recirculation zone, contributing to the development of an additional structure damage zone. The challenge of this study was also to determine the operating parameters of the HDA that would provide for an increase in methane production with positive energy balance. The testing procedures, for which maize silage was selected, involved batch disintegration tests and biochemical methane potential tests. No clogging of rotor or spontaneous shutting off of the device, in other words, problems that had occurred in the HDS, were observed. The applied pre-treatment method permitted an increase in the methane potential of maize silage by 34.4%, 27.0%, and 21.6%, respectively for samples disintegrated at energy densities of 10 kJ/L, 20 kJ/L, and 35 kJ/L with net energy profit.

Effect of three pretreatment techniques on the chemical composition and on the methane yields of Opuntia ficus-indica (prickly pear) biomass

2017 ◽  
Vol 36 (1) ◽  
pp. 17-29 ◽  
Author(s):  
PS Calabrò ◽  
E Catalán ◽  
A Folino ◽  
A Sánchez ◽  
D Komilis
Keyword(s):  
Chemical Composition ◽  
Methane Production ◽  
Lignin Content ◽  
Alkaline Treatment ◽  
Methane Yield ◽  
Opuntia Ficus Indica ◽  
Methane Generation ◽  
Methane Potential ◽  
Methane Production Rate ◽  
Experimental Values

Opuntia ficus-indica (OFI) is an emerging biomass that has the potential to be used as substrate in anaerobic digestion. The goal of this work was to investigate the effect of three pretreatment techniques (thermal, alkaline, acidic) on the chemical composition and the methane yield of OFI biomass. A composite experimental design with three factors and two to three levels was implemented, and regression modelling was employed using a total of 10 biochemical methane potential (BMP) tests. The measured methane yields ranged from 289 to 604 NmL/gVSadded; according to the results, only the acidic pretreatment (HCl) was found to significantly increase methane generation. However, as the experimental values were quite high with regards to the theoretical methane yield of the substrate, this effect still needs to be confirmed via further research. The alkaline pretreatment (NaOH) did not noticeably affect methane yields (an average reduction of 8% was recorded), despite the fact that it did significantly reduce the lignin content. Thermal pretreatment had no effect on the methane yields or the chemical composition. Scanning electron microscopy images revealed changes in the chemical structure after the addition of NaOH and HCl. Modelling of the cumulated methane production by the Gompertz modified equation was successful and aided in understanding kinetic advantages linked to some of the pretreatments. For example, the alkaline treatment (at the 20% dosage) at room temperature resulted to a μmax (maximum specific methane production rate [NmLCH4/(gVSadded·d)]) equal to 36.3 against 18.6 for the control.

scholarly journals Chemical pre-treatments on oil palm empty fruit bunches: Impacts on characteristics and methane potential

2021 ◽  
Vol 924 (1) ◽  
pp. 012071
Author(s):  
N A Rohma ◽  
S Suhartini ◽  
I Nurika
Keyword(s):  
Lignocellulosic Biomass ◽  
Oil Palm ◽  
Biogas Production ◽  
Lignin Content ◽  
Test System ◽  
Biochemical Methane Potential ◽  
Empty Fruit Bunches ◽  
Methane Potential ◽  
Pre Treatment ◽  
Bmp Test

Abstract Production of biogas from lignocellulosic biomass by anaerobic digestion (AD) has attracted much interest. Oil palm empty fruit bunches (OPEFB), one of lignocellulosic biomass, is highly abundant in Indonesia and has potential as feedstock for bioenergy production such as biogas or methane. Yet, pre-treatments are needed to improve biogas production due to its complex crystalline structures. Chemical pre-treatments with acid or alkaline solution were reported to increase cellulose or highly reduce the lignin content of OPEFB. This study aimed to evaluate the effect of acid and alkaline pre-treatments on the characteristics of OPEFB and methane potential. The acid pre-treatment experimental design was used factor of H2SO4 concentration (1, 1.3, and 1.6 (%v/v)) and NaOH concentration (1.8, 2.8, and 3.8 (%w/v)). Methane potential evaluation was carried out using the biochemical methane potential (BMP) test with the Automatic Methane Potential Test System (AMPTS) II under mesophilic condition (37°C), operated for 28 days. The results showed that both dilute acid and alkaline pre-treatment positively impact altering the characteristics of OPEFB, hence the specific methane potential. Alkaline pre-treatment with NaOH 3.8 (%w/v) gave the highest average SMP value of 0.161 ± 0.005 m3 CH4/kgVSadded.

scholarly journals Influence of conditioning agents and enzymic hydrolysis on the biochemical methane potential of sewage sludge

2013 ◽  
Vol 68 (7) ◽  
pp. 1622-1632 ◽  
Author(s):  
Elena Marañón ◽  
Luis Negral ◽  
Yolanda Fernández-Nava ◽  
Leonor Castrillón
Keyword(s):  
Sewage Sludge ◽  
Methane Production ◽  
Wastewater Treatment Plants ◽  
Solid Phase ◽  
Enzymic Hydrolysis ◽  
Biochemical Methane Potential ◽  
General Improvement ◽  
Methane Potential ◽  
Pre Treatment ◽  
Cationic Polyelectrolytes

Biochemical methane potential (BMP) tests have been carried out on sewage sludge from two wastewater treatment plants to assess the effect of additives (FeCl3 and two cationic polyelectrolytes) used in sludge dewatering. BMP tests were also carried out on the concentrated solid phase from the enzymic hydrolysis pre-treatment (42 °C, 48 h). FeCl3 had no significant effect on specific methane production, obtaining 242–246 LCH4/kgVSo. The effect of the combination of polyelectrolyte and FeCl3 depended on the polyelectrolyte and the sludge, but generally led to an increase in specific methane production (25–40%). When enzymic hydrolysis was applied as a pre-treatment, specific methane production increased from 6.8% in the sludge containing FeCl3 to 20% in the sludge without FeCl3, although the increases were not statistically significant. In terms of LCH4/kgVSrem, a general improvement was achieved both by means of additives and by enzymic hydrolysis. However, this improvement was only significant in the case of sludge which had undergone previous enzymic hydrolysis (62%) and in the untreated sludge containing a polyelectrolyte and FeCl3 (24%). Cationic polyelectrolytes inhibited solid–liquid separation during enzymic hydrolysis and, although the presence of only FeCl3 did not affect this separation, a significant decrease (32%) in LCH4/kgVSrem was observed.

Bio-Methane Potential (BMP) of Cassava Pulp Waste and Effect of Alkaline Pre-Treatment

2021 ◽  
Vol 31 (4) ◽  
pp. 26-31
Keyword(s):  
Lignin Content ◽  
Dry Weight ◽  
Cassava Starch ◽  
Untreated Sample ◽  
Processing Industry ◽  
Cassava Pulp ◽  
Surrounding Environment ◽  
Methane Potential ◽  
Pre Treatment ◽  
Bmp Test

Cassava starch processing industry produces cassava pulp as a by-product or waste. In the well-known Duong Lieu village, this waste is released in surrounding environment without treatment causing serious environmental problems. The study aimed to (1) determine the Biomethane Potential (BMP) of the waste and to (2) find out if alkaline pre-treatment would improve it. Different cassava pulp samples were going through BMP test: untreated sample; pre-treated samples at different NaOH doses of 2, 6, 8 wt.% (dry weight-based) and pre-treated samples at different NaHCO3 doses of 2, 4, 6, 8 wt.% (dry weight based). BMP assays were conducted in 590mL bottles at 37oC for 40 days. As the result, BMP of the untreated waste was 281 NmLCH4/gVS and alkaline pretreatment increased BMP of the waste up to 479 mLCH4/gVS by treatment with NaOH 6 wt.% and 450 mLCH4/gVS by treatment with NaHCO3 6 wt.%. In addition, there was a significant reduction of lignin content of the substrate after alkaline pre-treatment. The results show that cassava pulp waste has moderate potential for biogas recovery. In addition, alkaline pre-treatment by either NaOH or NaHCO3 would significantly improve its BMP, possibly thanks to the reduction of lignin content.

scholarly journals Efficiency of integrated electrooxidation and anaerobic digestion of waste activated sludge

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
J. A. Barrios ◽  
A. Cano ◽  
F. F. Rivera ◽  
M. E. Cisneros ◽  
U. Durán
Keyword(s):  
Anaerobic Digestion ◽  
Current Density ◽  
Methane Production ◽  
Energy Recovery ◽  
Energy Analysis ◽  
Mathematical Optimization ◽  
Waste Activated Sludge ◽  
Bdd Electrode ◽  
Vs Removal ◽  
Pre Treatment

Abstract Background Most of the organic content of waste activated sludge (WAS) comprises microbial cells hard to degrade, which must be pre-treated for energy recovery by anaerobic digestion (AD). Electrooxidation pre-treatment (EOP) with boron-doped diamond (BDD) electrode have been considered a promising novel technology that increase hydrolysis rate, by the disintegrating cell walls from WAS. Although electrochemical oxidation could efficiently solubilize organic substances of macromolecules, limited reports are available on EOP of WAS for improving AD. In this endeavour, the mathematical optimization study and the energy analysis of the effects of initial total solids concentrations [TS] of WAS and current density (CD) during EOP on the methane production and removal of chemical oxygen demand (COD) and volatile solids (VS) were investigated. Because limited reports are available on EOP of WAS for improving biogas production, it is not well understood; however, it has started to attract interest of scientists and engineers. Results In the present work, the energy recovery as biogas and WAS conversion were comprehensively affected by CD and [TS], in an integrated EOP and AD system. When working with WAS at 3% of [TS] pre-treated at current density of 24.1 mA/cm2, the highest COD and VS removal were achieved, making it possible to obtain the maximum methane (CH4) production of 305 N-L/kg VS and a positive energy balance of 1.67 kWh/kg VS. Therefore, the current densities used in BDD electrode are adequate to produce the strong oxidant (hydroxyl radical, ·OH) on the electrode surface, allow the oxidation of organic compounds that favours the solubilization of particulate matter and VS from WAS. Conclusions The improvement of VS removal and COD solubilization were due to the effects of pre-treatments, which help to break down the microbial cells for faster subsequent degradation; this allows a decomposition reaction that leads to biodegrade more compounds during AD. The balance was positive, suggesting that even without any optimization the energy used as electricity could be recovered from the increased methane production. It is worth noting that this kind of analysis have not been sufficiently studied so far. It is therefore important to understand how operational parameters can influence the pre-treatment and AD performances. The current study highlights that the mathematical optimization and energy analysis can make the whole process more convenient and feasible.

scholarly journals Delignification of Date Palm Fronds using Modified Organosolv Technique

2017 ◽  
Vol 13 (3) ◽  
pp. 1-9
Author(s):  
Yasmeen Salih Mahdi ◽  
Asem Hassan Mohammed ◽  
Alaa Kareem Mohammed
Keyword(s):  
Date Palm ◽  
Lignin Content ◽  
Statistical Experimental Design ◽  
Digestion Time ◽  
Stainless Steel Reactor ◽  
Pre Treatment ◽  
Design Type ◽  
Palm Fronds ◽  
Central Composite ◽  
High Lignin Content

Abstract   In this study, modified organic solvent (organosolv) method was applied to remove high lignin content in the date palm fronds (type Al-Zahdi) which was taken from the Iraqi gardens. In modified organosolv, lignocellulosic material is fractionated into its constituents (lignin, cellulose and hemicellulose). In this process, solvent (organic)-water is brought into contact with the lignocellulosic biomass at high temperature, using stainless steel reactor (digester). Therefor; most of hemicellulose will remove from the biomass, while the solid residue (mainly cellulose) can be used in various industrial fields. Three variables were studied in this process: temperature, ratio of ethanol to water and digestion time. Statistical experimental design type Central Composite Design (CCD) has been used to find a mathematical relationship between the variables and the remaining lignin percent as dependent variable. The results obtained in this study were represented by a polynomial mathematical equation of the second degree.  The results showed that the best digestion time was (80 minutes), which gave the best percent remaining concentration of lignin (3%) at temperature of 185oC and ratio of ethanol: water equal to 50: 50 wt/wt. In order to reduce digesting time, the effect of using different catalysts have been studied such as (NaOH, H2SO4, Ca (OH) 2) at low concentration (0.025, 0.025, 0.05M) respectively. It was found that the best catalyst is sodium hydroxide at concentration (0.025) mol/L which gave the same percent of  lignin 3% but with low digestion time about 30 min. Keywords: Biomass pre-treatment, delignification, lignin, organosolv, date palm fronds.

Anaerobic digestion of macroalgae: methane potentials, pre-treatment, inhibition and co-digestion

2011 ◽  
Vol 64 (8) ◽  
pp. 1723-1729 ◽  
Author(s):  
H. B. Nielsen ◽  
S. Heiske
Keyword(s):  
Anaerobic Digestion ◽  
Methane Production ◽  
Organic Content ◽  
Saccharina Latissima ◽  
Green Tides ◽  
Volatile Solids ◽  
Continuously Stirred Tank Reactor ◽  
Pre Treatment ◽  
Centralized Biogas Plant ◽  
Chaetomorpha Linum

In the present study we tested four macroalgae species – harvested in Denmark – for their suitability of bioconversion to methane. In batch experiments (53 °C) methane yields varied from 132 ml g volatile solids−1 (VS) for Gracillaria vermiculophylla, 152 ml g VS−1 for Ulva lactuca, 166 ml g VS−1 for Chaetomorpha linum and 340 ml g VS−1 for Saccharina latissima following 34 days of incubation. With an organic content of 21.1% (1.5–2.8 times higher than the other algae) S. latissima seems very suitable for anaerobic digestion. However, the methane yields of U. lactuca, G. vermiculophylla and C. linum could be increased with 68%, 11% and 17%, respectively, by pretreatment with maceration. U. lactuca is often observed during ‘green tides’ in Europe and has a high cultivation potential at Nordic conditions. Therefore, U. lactuca was selected for further investigation and co-digested with cattle manure in a lab-scale continuously stirred tank reactor. A 48% increase in methane production rate of the reactor was observed when the concentration of U. lactuca in the feedstock was 40% (VS basis). Increasing the concentration to 50% had no further effect on the methane production, which limits the application of this algae at Danish centralized biogas plant.

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