Optimization of dilute acetic acid pretreatment of mixed fruit waste for increased methane production

Saha, Shouvik,Jeon, Byong-Hun,Kurade, Mayur B.,Jadhav, Shekhar B.,Chatterjee, Pradip K.,Chang, Soon Woong,Govindwar, Sanjay Prabhu,Kim, Sun Joon Elsevier 2018 Journal of cleaner production Vol.190 No.-

<P><B>Abstract</B></P> <P>A proper waste management practice such as anaerobic digestion for the waste generated by the agro-food industries could minimize the amount of material disposal to landfill. In our study, the improvement of methane production was elucidated through the pretreatment optimization of the mixed fruit wastes (FW). Dilute acetic acid pretreatment of FW was optimized in order to increase the bioavailability and microbial accessibility. A maximum sugar recovery of 95% was achieved from the pretreated FW under the optimized conditions (0.2 M acetic acid, 62.5 °C, and 30 min). Fourier transform infrared spectroscopy (FTIR) and Thermogravimetric (TG) analyses verified the presence of cellulosic material in the pretreated FW. X-ray diffraction (XRD) analysis indicated that the crystallinity index was increased to 56% after the disruption of complex hemicellulosic structures during pretreatment. Increased porosity and surface roughness of pretreated FW for better microbial attachment were confirmed in scanning electron microscopy (SEM). Anaerobic digestion showed increased methanogenic activity (10.17 mL g<SUP>−1</SUP> VS<SUB>initial</SUB> d<SUP>−1</SUP>) in pretreated FW, during 86-day experimental period due to better microbial attachment and accessibility during the digestion process. Higher methane yield of 53.58 mL g<SUP>−1</SUP> VS<SUB>initial</SUB> was observed in pretreated FW. Thus, acetic acid pretreatment is an effective method to improve the utilization and conversion of FW to methane.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Fruit waste pretreatment was optimized by employing RSM. </LI> <LI> Under optimized conditions, pretreatment recovered 95% of the total sugar. </LI> <LI> Optimized pretreatment improved methane yield by 10%. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Microbial acclimatization to lipidic-waste facilitates the efficacy of acidogenic fermentation

Saha, Shouvik,Jeon, Byong-Hun,Kurade, Mayur B.,Chatterjee, Pradip K.,Chang, Soon Woong,Markkandan, Kesavan,Salama, El-Sayed,Govindwar, Sanjay P.,Roh, Hyun-Seog Elsevier 2019 CHEMICAL ENGINEERING JOURNAL -LAUSANNE- Vol.358 No.-

<P><B>Abstract</B></P> <P>Lipidic-waste such as fat, oil, and grease (FOG) are promising substrates for achieving higher bioenergy yields. An inadequate presence of an effective microbiome in the anaerobic digesters is the bottleneck for the proper utilization of FOG. Gradual introduction of FOG (0.2%, 1.2%, and 2.4% as volatile solids) in acidogenic fermentation showed a significant improvement in hydrogen yield (72%), compared to the control, after 2.4% FOG loading. Volatile solid (VS) reduction reached up to 65% in high FOG reactors with complete removal of major unsaturated fatty acids. Removal of saturated fatty acids increased to 90%. Improvement in hydrogen productivity (46 mL d<SUP>−1</SUP>) occurred during step-wise loading of 2.4% FOG to the acclimatized microbiome. The metabolic shift toward carboxylic chain elongation produced C4 and C6 fatty acids at concentrations of 1.61 mM and 0.90 mM, respectively in the acidogenic reactors. High-throughput sequencing of 16S rRNA amplicons revealed that the acclimatization process enriched the phylum Firmicutes (90%), followed by Bacteroidetes (12%) and Cloacimonetes (11%). The abundance of these phyla and their respective genera confirmed their preeminent role in hydrolysis, hydrogenogenic acidogenesis, and carboxylic chain elongation to produce hydrogen and C4–C7 fatty acids. Thus, we suggest that the improvement of hydrogen production using a microbiome acclimatized to FOG, and simultaneous production of high value organics (C4–C7 fatty acids), could facilitate the greater efficacy of the acidogenic fermentation.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Microbial acclimatization improved lipidic-waste utilization in acidogenic fermentation. </LI> <LI> Firmicutes, Bacteroidetes, and Cloacimonetes were abundant in the acclimatized microbiome. </LI> <LI> Hydrogen productivity enhanced to 46 mL d<SUP>−1</SUP> after acclimatization. </LI> <LI> Hydrogenogenic acidogenesis and carboxylic chain elongation produced C4–C7 fatty acids. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Perspective on anaerobic digestion for biomethanation in cold environments

Dev, Subhabrata,Saha, Shouvik,Kurade, Mayur B.,Salama, El-Sayed,El-Dalatony, Marwa M.,Ha, Geon-Soo,Chang, Soon Woong,Jeon, Byong-Hun Elsevier 2019 RENEWABLE & SUSTAINABLE ENERGY REVIEWS Vol.103 No.-

<P><B>Abstract</B></P> <P>The anaerobic digestion (AD) has become an important part of the wastewater treatment plants that regulates the sustainable management of organic wastes with simultaneous production of bioenergy. AD at low temperatures using psychrophilic anaerobes with optimum growth temperatures < 20 °C has gained significant attention for improvement of biogas productivity in cold regions. The present review discusses the detailed characteristics of psychrophilic anaerobes, and how the properties of those particular psychrophiles can be utilized towards the cost-effective production of methane at cold environment. The different challenges for AD at low temperature have been described thoroughly. The various strategies such as (a) adaptation of microbial community, (b) optimization of operational parameters, (c) utilization of specialized biodigester design, and (d) modification of downstream process to improve the AD and biomethane production in cold environments have also been summarized. The present review proposes the future technological developments which should be aimed at effective performance of anaerobic digesters to improve biomethanation in cold regions.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Psychrophilic AD is an energy efficient process for biomethanation in cold regions. </LI> <LI> Alterations of cellular physiology increases the adaptive response in psychrophiles. </LI> <LI> Cold adaptation of inoculum and process optimization could improve psychrophilic AD. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Pretreatment of polysaccharidic wastes with cellulolytic <i>Aspergillus fumigatus</i> for enhanced production of biohythane in a dual-stage process

Basak, Bikram,Saha, Shouvik,Chatterjee, Pradip K.,Ganguly, Amit,Woong Chang, Soon,Jeon, Byong-Hun Elsevier Applied Science 2020 Bioresource Technology Vol. No.

<P><B>Abstract</B></P> <P>Biological pretreatment of polysaccharidic wastes (PWs) is a cost-effective and environmentally friendly approach to improve the digestibility and utilization of these valuable substrates in dual-stage biohythane production. In order to reduce the prolonged incubation time and loss of carbohydrate during the pretreatment of PWs with <I>Aspergillus fumigatus</I>, a systematic optimization using Taguchi methodology resulted in an unprecedented recovery of soluble carbohydrates (362.84 mg g<SUP>−1</SUP>) within 5 days. The disruption and fragmentation of lignocellulosic structures in PWs, and possible saccharification of cellulose and hemicellulose components, increased its digestibility. A dual-stage biohythane production with pretreated PWs showed increased yield (214.13 mL g<SUP>−1</SUP> VS<SUB>added</SUB>), which was 56% higher than the corresponding value with the untreated PWs. This resulted in 47% higher energy recovery as biohythane in pretreated biomass compared to untreated biomass. Optimized fungal pretreatment is, therefore, an effective method to improve the digestibility of PWs and its subsequent conversion to biohythane.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Optimization of fungal pretreatment reduced the pretreatment time and sugar loss. </LI> <LI> Optimized fungal pretreatment solubilized 53% of the total sugar. </LI> <LI> Dual-stage biohythane process resulted in 62% reduction in TS in pretreated biomass. </LI> <LI> Energy recovery as biohythane improved by 47% with fungal pretreated biomass. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Remediation of cyanide-contaminated environments through microbes and plants: a review of current knowledge and future perspectives

RAHUL KUMAR,Shouvik Saha,Sarita Dhaka,Mayur B. Kurade,강찬웅,백승한,전병훈 한국자원공학회 2017 Geosystem engineering Vol.20 No.1

Mining industry has been using cyanide for more than ten decades to recover precious metals such as gold and silver. The presence of cyanide in the environment has long been a matter of concern due to its high toxicity to human, animal, and aquatic life. The available treatment processes either physical or chemical are suffered with issues such as operating conditions, generation of secondary pollution, and lack of cost effectiveness. A number of micro-organisms are capable to consume cyanide as a source of carbon and nitrogen, and convert it into ammonia and carbonate. Some plants are also efficient in cyanide attenuation process. Bioremediation of cyanide might be an efficient, cost-effective, eco-friendly, and an attractive alternative to the conventional physical and chemical processes. This paper reviews the recent advances in remediation of cyanide contaminated tailings via micro-organisms and plants. Aspects such as speciation, toxicity, source, and degradation mechanisms of cyanide are discussed. Factors affecting functioning of micro-organisms and plants as bioremediation agents are also highlighted.

Microbial community acclimatization for enhancement in the methane productivity of anaerobic co-digestion of fats, oil, and grease

Kurade, Mayur B.,Saha, Shouvik,Kim, Jung Rae,Roh, Hyun-Seog,Jeon, Byong-Hun Elsevier Applied Science 2020 Bioresource Technology Vol. No.

<P><B>Abstract</B></P> <P>The methane productivity and long chain fatty acids (LCFAs) degradation capability of unacclimatized seed sludge (USS) and acclimatized seed sludge (ASS) at different substrate ratios of fats oil and grease (FOG) and mixed sewage sludge were investigated in this study. Biogas produced in ASS in initial phase of anaerobic digestion had higher methane content (65–76%) than that in USS (26–73%). The degradation of major LCFAs in the ASS was 22–80%, 33–191%, and 7–64% higher for the substrate ratios of 100:10, 100:20, and 100:30, respectively, as compared to the LCFAs’ degradation in USS. Microbial acclimatization increased the population of Firmicutes (40%), Bacteroidetes (32%), Synergistetes (10%), and Euryarchaeota (8%) in ASS, which supported the faster rate of LCFAs degradation for its later conversion to methane. The significant abundance of <I>Syntrophomonas</I> and <I>Methanosarcina</I> genera in ASS supported faster generation rate of methane in an obligatory syntrophic relationship.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Methane productivity of unacclimatized and acclimatized sludge were investigated. </LI> <LI> Biogas produced in ASS showed higher methane content (65–76%) than in USS (26–73%). </LI> <LI> The ASS exhibited greater degradation of LCFAs than in USS. </LI> <LI> Firmicutes, Bacteroidetes, Synergistetes and Euryarchaeota were highly increased. </LI> <LI> Abundance of <I>Syntrophomonas</I> and <I>Methanosarcina</I> in ASS improved methane generation. </LI> </UL> </P>

Improvement of acidogenic fermentation using an acclimatized microbiome

Chang, Sung-Eun,Saha, Shouvik,Kurade, Mayur B.,Salama, El-Sayed,Chang, Soon Woong,Jang, Min,Jeon, Byong-Hun Elsevier 2018 International journal of hydrogen energy Vol.43 No.49

<P><B>Abstract</B></P> <P>Mixed fruit wastes (FW) are considered valuable organic wastes due to their polysaccharidic content. This study describes utilization of an effective acclimatized microbiome (AM) for enhanced conversion of FW into hydrogen and various value-added byproducts. Microbial acclimatization was used to accelerate two processes, hydrogenogenic acidogenesis and carboxylic chain elongation, which simultaneously produced hydrogen and C4C7 carboxylates. AM showed 77 mL g‾<SUP>1</SUP> VS of hydrogen yield with 31% higher specific hydrogen production potential (SHPP) compared to 55 mL g‾<SUP>1</SUP> VS with an unacclimatized microbiome (UM). Production of carboxylates was also 19% higher in the AM. Taxonomic analysis of the microbiome revealed the microbial shift to Firmicutes as the most dominant phylum (99%). <I>Clostridium</I>, <I>Hydrogenoanaerobacterium</I>, <I>Paraclostridium</I>, <I>Anaerosalibacter</I>, <I>Tissierella</I>, and <I>Tepidanaerobacter</I> were preeminent genera in the AM, confirming their predominant role in dual processes. Thus, utilization of an AM enhanced the hydrogenogenic acidogenic fermentation of FW with simultaneous carboxylic chain elongation, yielding high-value products.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Use of an acclimatized microbiome improved the hydrogen yield by 48%. </LI> <LI> Firmicutes was the most dominant phylum in the acclimatized microbiome. </LI> <LI> <I>Clostridium</I> showed substrate specificity to polysaccharidic–wastes. </LI> <LI> Acclimatization facilitated hydrogenogenic acidogenesis and chain elongation. </LI> </UL> </P>

Biological Conversion of Amino Acids to Higher Alcohols

El-Dalatony, Marwa M.,Saha, Shouvik,Govindwar, Sanjay P.,Abou-Shanab, Reda A.I.,Jeon, Byong-Hun Elsevier 2019 Trends in biotechnology Vol.37 No.8

<P>‘Higher’ alcohols, which contain more than two carbons, have a higher boiling point, higher cetane number, and higher energy density than ethanol. Blends of biodiesel and higher alcohols can be used in internal combustion engines as next-generation biofuels without any modification and are minimally corrosive over extensive use. Producing higher alcohols from biomass involves fermenting and metabolizing amino acids. In this review, we describe the pathways and regulatory mechanisms involved in amino acid bioprocessing to produce higher alcohols and the effects of amino acid supplementation as a nitrogen source for higher alcohol production. We also discuss the most recent approaches to improve higher alcohol production via genetic engineering technologies for three microorganisms: <I>Saccharomyces cerevisiae</I>, <I>Clostridium</I> spp., and <I>Escherichia coli</I>.</P> <P><B>Highlights</B></P> <P>Proteins are polymers of various amino acids, connected via peptide bonds and classified as a major feedstock for bioenergy production. Higher alcohols are high-density alternative fuels that increase the longevity of transportation fuels.</P> <P>Proteins have a significant role in the fermentation process by providing amino acids for the growth of microorganisms, and enhancement of sugar permeability, in carbohydrate-rich sources.</P> <P>Due to the environmental and economic advantages of recombinant DNA technology, fermentation is the most used process for industrial-scale alcohol production. Applying this technology to higher alcohols can significantly improve industrialization for advanced fuel production.</P> <P>Extraction techniques are used to separate and mitigate the toxicity of alcohols produced in the fermentation broth to maintain the microbial cell viability for longer.</P>

Acetoclastic methanogenesis led by <i>Methanosarcina</i> in anaerobic co-digestion of fats, oil and grease for enhanced production of methane

Kurade, Mayur B.,Saha, Shouvik,Salama, El-Sayed,Patil, Swapnil M.,Govindwar, Sanjay P.,Jeon, Byong-Hun Elsevier Applied Science 2019 Bioresource Technology Vol. No.

<P><B>Abstract</B></P> <P>Fats, oil and grease (FOG) are energy-dense wastes that substantially increase biomethane recovery. Shifts in the microbial community during anaerobic co-digestion of FOG was assessed to understand relationships between substrate digestion and microbial adaptations. Excessive addition of FOG inhibited the methanogenic activity during initial phase; however, it enhanced the ultimate methane production by 217% compared to the control. The dominance of Proteobacteria was decreased with a simultaneous increase in Firmicutes, Bacteriodetes, Synergistetes and Euryarchaeota during the co-digestion. A significant increase in <I>Syntrophomonas</I> (0.18–11%), <I>Sporanaerobacter</I> (0.14–6%) and <I>Propionispira</I> (0.02–19%) was observed during co-digestion, which substantiated their importance in acetogenesis. Among methanogenic Archaea, the dominance of <I>Methanosaeta</I> (94%) at the beginning of co-digestion was gradually replaced by <I>Methanosarcina</I> (0.52–95%)<I>.</I> The absence/relatively low abundance of syntrophic acetate oxidizers and hydrogenotrophic methanogens, and dominance of acetoclastic methanogens suggested that methane generation during co-digestion of FOG was predominantly conducted through acetoclastic pathway led by <I>Methanosarcina</I>.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The addition of fats, oil and grease enhanced ultimate methane production by 217%. </LI> <LI> Firmicutes, Bacteriodetes, Synergistetes and Euryarchaeota were greatly increased. </LI> <LI> Dominance of <I>Methanosaeta</I> was replaced by <I>Methanosarcina</I> at the end of digestion. </LI> <LI> Methane was predominantly generated through acetoclastic pathway by <I>Methanosarcina</I>. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>