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Chandrasekar M, Collins JL, Habibi S, Ong RG. Microfluidic reactor designed for time-lapsed imaging of pretreatment and enzymatic hydrolysis of lignocellulosic biomass. Bioresour Technol 2024; 393:129989. [PMID: 37931765 DOI: 10.1016/j.biortech.2023.129989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 10/25/2023] [Accepted: 11/03/2023] [Indexed: 11/08/2023]
Abstract
The effect of tissue-specific biochemical heterogeneities of lignocellulosic biomass on biomass deconstruction is best understood through confocal laser scanning microscopy (CLSM) combined with immunohistochemistry. However, this process can be challenging, given the fragility of plant materials, and is generally not able to observe changes in the same section of biomass during both pretreatment and enzymatic hydrolysis. To overcome this challenge, a custom polydimethylsiloxane (PDMS) microfluidic imaging reactor was constructed using standard photolithographic techniques. As proof of concept, CLSM was performed on 60 μm-thick corn stem sections during pretreatment and enzymatic hydrolysis using the imaging reactor. Based on the fluorescence images, the less lignified parenchyma cell walls were more susceptible to pretreatment than the lignin-rich vascular bundles. During enzymatic hydrolysis, the highly lignified protoxylem cell wall was the most resistant, remaining unhydrolyzed even after 48 h. Therefore, imaging thin whole biomass sections was useful to obtain tissue-specific changes during biomass deconstruction.
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Affiliation(s)
- Meenaa Chandrasekar
- Department of Chemical Engineering, Michigan Technological University, 1400 Townsend Drive, Houghton, 49931, MI, USA; DOE Great Lakes Bioenergy Research Center, Michigan Technological University, 1400 Townsend Drive, Houghton, 49931, MI, USA
| | - Jeana L Collins
- Department of Chemical Engineering, Michigan Technological University, 1400 Townsend Drive, Houghton, 49931, MI, USA
| | - Sanaz Habibi
- Department of Chemical Engineering, Michigan Technological University, 1400 Townsend Drive, Houghton, 49931, MI, USA
| | - Rebecca G Ong
- Department of Chemical Engineering, Michigan Technological University, 1400 Townsend Drive, Houghton, 49931, MI, USA; DOE Great Lakes Bioenergy Research Center, Michigan Technological University, 1400 Townsend Drive, Houghton, 49931, MI, USA.
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2
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Putman LI, Schaerer LG, Wu R, Kulas DG, Zolghadr A, Ong RG, Shonnard DR, Techtmann SM. Deconstructed Plastic Substrate Preferences of Microbial Populations from the Natural Environment. Microbiol Spectr 2023; 11:e0036223. [PMID: 37260392 PMCID: PMC10433879 DOI: 10.1128/spectrum.00362-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 05/09/2023] [Indexed: 06/02/2023] Open
Abstract
Over half of the world's plastic waste is landfilled, where it is estimated to take hundreds of years to degrade. Given the continued use and disposal of plastic products, it is vital that we develop fast and effective ways to utilize plastic waste. Here, we explore the potential of tandem chemical and biological processing to process various plastics quickly and effectively. Four samples of compost or sediment were used to set up enrichment cultures grown on mixtures of compounds, including disodium terephthalate and terephthalic acid (monomers of polyethylene terephthalate), compounds derived from the chemical deconstruction of polycarbonate, and pyrolysis oil derived from high-density polyethylene plastics. Established enrichment communities were also grown on individual substrates to investigate the substrate preferences of different taxa. Biomass harvested from the cultures was characterized using 16S rRNA gene amplicon sequencing and shotgun metagenomic sequencing. These data reveal low-diversity microbial communities structured by differences in culture inoculum, culture substrate source plastic type, and time. Microbial populations from the classes Alphaproteobacteria, Gammaproteobacteria, Actinobacteria, and Acidobacteriae were significantly enriched when grown on substrates derived from high-density polyethylene and polycarbonate. The metagenomic data contain abundant aromatic and aliphatic hydrocarbon degradation genes relevant to the biodegradation of deconstructed plastic substrates used here. We show that microbial populations from diverse environments are capable of growth on substrates derived from the chemical deconstruction or pyrolysis of multiple plastic types and that paired chemical and biological processing of plastics should be further developed for industrial applications to manage plastic waste. IMPORTANCE The durability and impermeable nature of plastics have made them a popular material for numerous applications, but these same qualities make plastics difficult to dispose of, resulting in massive amounts of accumulated plastic waste in landfills and the natural environment. Since plastic use and disposal are projected to increase in the future, novel methods to effectively break down and dispose of current and future plastic waste are desperately needed. We show that the products of chemical deconstruction or pyrolysis of plastic can successfully sustain the growth of low-diversity microbial communities. These communities were enriched from multiple environmental sources and are capable of degrading complex xenobiotic carbon compounds. This study demonstrates that tandem chemical and biological processing can be used to degrade multiple types of plastics over a relatively short period of time and may be a future avenue for the mitigation of rapidly accumulating plastic waste.
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Affiliation(s)
- Lindsay I. Putman
- Department of Biological Sciences, Michigan Technological University, Houghton, Michigan, USA
| | - Laura G. Schaerer
- Department of Biological Sciences, Michigan Technological University, Houghton, Michigan, USA
| | - Ruochen Wu
- Department of Chemical Engineering, Michigan Technological University, Houghton, Michigan, USA
| | - Daniel G. Kulas
- Department of Chemical Engineering, Michigan Technological University, Houghton, Michigan, USA
| | - Ali Zolghadr
- Department of Chemical Engineering, Michigan Technological University, Houghton, Michigan, USA
| | - Rebecca G. Ong
- Department of Chemical Engineering, Michigan Technological University, Houghton, Michigan, USA
| | - David R. Shonnard
- Department of Chemical Engineering, Michigan Technological University, Houghton, Michigan, USA
| | - Stephen M. Techtmann
- Department of Biological Sciences, Michigan Technological University, Houghton, Michigan, USA
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3
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Putman LI, Schaerer LG, Wu R, Kulas DG, Zolghadr A, Ong RG, Shonnard DR, Techtmann SM, Arbanas LG, Bannerman GG, Cart B, Cureton A, Doerr BP, Jovicevic Z, Langosch M, MacLeod AB, McCloskey C, McNally AM, Monkevich MK, Noecker A, Norris D, Pellizzon VG, Strom KB, Taylor EE. Metagenomic Sequencing of Two Cultures Grown on Chemically Deconstructed Plastic Products. Microbiol Resour Announc 2023:e0130422. [PMID: 37338395 DOI: 10.1128/mra.01304-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 06/01/2023] [Indexed: 06/21/2023] Open
Abstract
We report the metagenome sequences of two microbial cultures that were grown with chemically deconstructed plastic products as their sole carbon source. These metagenomes will provide insights into the metabolic capabilities of cultures grown on deconstructed plastics and can serve as a starting point for the identification of novel plastic degradation mechanisms.
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Affiliation(s)
- Lindsay I Putman
- Department of Biological Sciences, Michigan Technological University, Houghton, Michigan, USA
| | - Laura G Schaerer
- Department of Biological Sciences, Michigan Technological University, Houghton, Michigan, USA
| | - Ruochen Wu
- Department of Chemical Engineering, Michigan Technological University, Houghton, Michigan, USA
| | - Daniel G Kulas
- Department of Chemical Engineering, Michigan Technological University, Houghton, Michigan, USA
| | - Ali Zolghadr
- Department of Chemical Engineering, Michigan Technological University, Houghton, Michigan, USA
| | - Rebecca G Ong
- Department of Chemical Engineering, Michigan Technological University, Houghton, Michigan, USA
| | - David R Shonnard
- Department of Chemical Engineering, Michigan Technological University, Houghton, Michigan, USA
| | - Stephen M Techtmann
- Department of Biological Sciences, Michigan Technological University, Houghton, Michigan, USA
| | - Lucille G Arbanas
- Department of Biological Sciences, Michigan Technological University, Houghton, Michigan, USA
| | - Gabriel G Bannerman
- Department of Biological Sciences, Michigan Technological University, Houghton, Michigan, USA
| | - Brice Cart
- Department of Biological Sciences, Michigan Technological University, Houghton, Michigan, USA
| | - Allen Cureton
- Department of Biological Sciences, Michigan Technological University, Houghton, Michigan, USA
| | - Benjamin P Doerr
- Department of Biological Sciences, Michigan Technological University, Houghton, Michigan, USA
| | - Zora Jovicevic
- Department of Biological Sciences, Michigan Technological University, Houghton, Michigan, USA
| | - Mary Langosch
- Department of Biological Sciences, Michigan Technological University, Houghton, Michigan, USA
| | - Aaron B MacLeod
- Department of Biological Sciences, Michigan Technological University, Houghton, Michigan, USA
| | - Caden McCloskey
- Department of Biological Sciences, Michigan Technological University, Houghton, Michigan, USA
| | - Avery M McNally
- Department of Biological Sciences, Michigan Technological University, Houghton, Michigan, USA
| | - Mykenzie K Monkevich
- Department of Biological Sciences, Michigan Technological University, Houghton, Michigan, USA
- Department of Chemistry, Michigan Technological University, Houghton, Michigan, USA
| | - Adrian Noecker
- Department of Biological Sciences, Michigan Technological University, Houghton, Michigan, USA
| | - Dylan Norris
- Department of Biological Sciences, Michigan Technological University, Houghton, Michigan, USA
| | - Vincent G Pellizzon
- Department of Chemistry, Michigan Technological University, Houghton, Michigan, USA
| | - Kylie B Strom
- Department of Biological Sciences, Michigan Technological University, Houghton, Michigan, USA
| | - Emily E Taylor
- Department of Biological Sciences, Michigan Technological University, Houghton, Michigan, USA
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Schaerer LG, Wood E, Aloba S, Byrne E, Bashir MA, Baruah K, Schumann E, Umlor L, Wu R, Lee H, Orme CJ, Wilson AD, Lacey JA, Ong RG, Techtmann SM. Versatile microbial communities rapidly assimilate ammonium hydroxide-treated plastic waste. J Ind Microbiol Biotechnol 2023; 50:7120041. [PMID: 37061790 PMCID: PMC10124128 DOI: 10.1093/jimb/kuad008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 03/15/2023] [Indexed: 04/17/2023]
Abstract
Most plastic waste accumulates in landfills or the environment. Natural microbial metabolisms can degrade plastic polymers. Unfortunately, biodegradation of plastics is slow even under ideal conditions; depolymerization of plastic is the rate limiting step. Rapid chemical depolymerization yields biodegradable plastic monomers, improving biodegradation rates. Here we demonstrate that ammonium hydroxide depolymerizes PET into terephthalic acid and terephthalic acid monoamide which are rapidly metabolized by diverse consortia obtained from compost and sediment. By neutralizing the product with phosphoric acid prior to bioprocessing, the final product contains plastic-derived carbon and biologically accessible nitrogen and phosphorus from the process reactants, removing the need for culture medium. Three microbial consortia were able to degrade chemically deconstructed PET in ultrapure water and scavenged river water without the addition of nutrients, with no statistically significant difference in growth rate compared to communities grown on deconstructed PET in Bushnell Haas minimal culture medium. The consortia were dominated by Rhodococcus spp., Hydrogenophaga spp., and many lower abundance genera. All taxa were related to species known to degrade aromatic compounds. Microbial consortia are known to confer flexibility in processing diverse substrates. To highlight the versatility of these consortia, we also demonstrate that two microbial consortia can grow on similarly deconstructed polyesters, polyamides, and polyurethanes in water instead of medium. Our findings suggest that using microbial communities enable flexible bioprocessing of mixed plastic wastes. We also demonstrate the flexibility of this approach for coupled chemical deconstruction and bioprocessing.
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Affiliation(s)
- Laura G Schaerer
- Department of Biological Sciences, Michigan Technological University, Houghton, MIUSA
| | - Emily Wood
- Department of Biological Sciences, Michigan Technological University, Houghton, MIUSA
| | - Sulihat Aloba
- Department of Chemical Engineering, Michigan Technological University, Houghton, MIUSA
| | - Emily Byrne
- Department of Biological Sciences, Michigan Technological University, Houghton, MIUSA
| | - M Aamir Bashir
- Department of Chemical Engineering, Michigan Technological University, Houghton, MIUSA
| | - Kaushik Baruah
- Department of Chemical Engineering, Michigan Technological University, Houghton, MIUSA
| | - Elizabeth Schumann
- Department of Chemical Engineering, Michigan Technological University, Houghton, MIUSA
| | - Libby Umlor
- Department of Chemical Engineering, Michigan Technological University, Houghton, MIUSA
| | - Ruochen Wu
- Department of Chemical Engineering, Michigan Technological University, Houghton, MIUSA
| | - Hyeonseok Lee
- Biological Processing Department, Idaho National Laboratory, ID Falls, ID USA
| | - Christopher J Orme
- Biological Processing Department, Idaho National Laboratory, ID Falls, ID USA
| | - Aaron D Wilson
- Biological Processing Department, Idaho National Laboratory, ID Falls, ID USA
| | - Jeffrey A Lacey
- Biological Processing Department, Idaho National Laboratory, ID Falls, ID USA
| | - Rebecca G Ong
- Department of Chemical Engineering, Michigan Technological University, Houghton, MIUSA
| | - Stephen M Techtmann
- Department of Biological Sciences, Michigan Technological University, Houghton, MIUSA
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Schaerer LG, Wu R, Putman LI, Pearce JM, Lu T, Shonnard DR, Ong RG, Techtmann SM. Killing two birds with one stone: chemical and biological upcycling of polyethylene terephthalate plastics into food. Trends Biotechnol 2023; 41:184-196. [PMID: 36058768 DOI: 10.1016/j.tibtech.2022.06.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 05/24/2022] [Accepted: 06/21/2022] [Indexed: 01/24/2023]
Abstract
Most polyethylene terephthalate (PET) plastic waste is landfilled or pollutes the environment. Additionally, global food production must increase to support the growing population. This article explores the feasibility of using microorganisms in an industrial system that upcycles PET into edible microbial protein powder to solve both problems simultaneously. Many microorganisms can utilize plastics as feedstock, and the resultant microbial biomass contains fats, nutrients, and proteins similar to those found in human diets. While microbial degradation of PET is promising, biological PET depolymerization is too slow to resolve the global plastic crisis and projected food shortages. Evidence reviewed here suggests that by coupling chemical depolymerization and biological degradation of PET, and using cooperative microbial communities, microbes can efficiently convert PET waste into food.
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Affiliation(s)
- Laura G Schaerer
- Department of Biological Sciences, Michigan Technological University, Houghton, MI, USA
| | - Ruochen Wu
- Department of Chemical Engineering, Michigan Technological University, Houghton, MI, USA
| | - Lindsay I Putman
- Department of Biological Sciences, Michigan Technological University, Houghton, MI, USA
| | - Joshua M Pearce
- Department of Electrical and Computer Engineering, Western University, London, Ontario, Canada
| | - Ting Lu
- Department of Bioengineering, University of Illinois Urbana-Champaign, Champaign, IL, USA
| | - David R Shonnard
- Department of Chemical Engineering, Michigan Technological University, Houghton, MI, USA
| | - Rebecca G Ong
- Department of Chemical Engineering, Michigan Technological University, Houghton, MI, USA
| | - Stephen M Techtmann
- Department of Biological Sciences, Michigan Technological University, Houghton, MI, USA.
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Chandrasekar M, Joshi L, Krieg K, Chipkar S, Burke E, Debrauske DJ, Thelen KD, Sato TK, Ong RG. A high solids field-to-fuel research pipeline to identify interactions between feedstocks and biofuel production. Biotechnol Biofuels 2021; 14:179. [PMID: 34507592 PMCID: PMC8431876 DOI: 10.1186/s13068-021-02033-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 08/30/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND Environmental factors, such as weather extremes, have the potential to cause adverse effects on plant biomass quality and quantity. Beyond adversely affecting feedstock yield and composition, which have been extensively studied, environmental factors can have detrimental effects on saccharification and fermentation processes in biofuel production. Only a few studies have evaluated the effect of these factors on biomass deconstruction into biofuel and resulting fuel yields. This field-to-fuel evaluation of various feedstocks requires rigorous coordination of pretreatment, enzymatic hydrolysis, and fermentation experiments. A large number of biomass samples, often in limited quantity, are needed to thoroughly understand the effect of environmental conditions on biofuel production. This requires greater processing and analytical throughput of industrially relevant, high solids loading hydrolysates for fermentation, and led to the need for a laboratory-scale high solids experimentation platform. RESULTS A field-to-fuel platform was developed to provide sufficient volumes of high solids loading enzymatic hydrolysate for fermentation. AFEX pretreatment was conducted in custom pretreatment reactors, followed by high solids enzymatic hydrolysis. To accommodate enzymatic hydrolysis of multiple samples, roller bottles were used to overcome the bottlenecks of mixing and reduced sugar yields at high solids loading, while allowing greater sample throughput than possible in bioreactors. The roller bottle method provided 42-47% greater liquefaction compared to the batch shake flask method for the same solids loading. In fermentation experiments, hydrolysates from roller bottles were fermented more rapidly, with greater xylose consumption, but lower final ethanol yields and CO2 production than hydrolysates generated with shake flasks. The entire platform was tested and was able to replicate patterns of fermentation inhibition previously observed for experiments conducted in larger-scale reactors and bioreactors, showing divergent fermentation patterns for drought and normal year switchgrass hydrolysates. CONCLUSION A pipeline of small-scale AFEX pretreatment and roller bottle enzymatic hydrolysis was able to provide adequate quantities of hydrolysate for respirometer fermentation experiments and was able to overcome hydrolysis bottlenecks at high solids loading by obtaining greater liquefaction compared to batch shake flask hydrolysis. Thus, the roller bottle method can be effectively utilized to compare divergent feedstocks and diverse process conditions.
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Affiliation(s)
- Meenaa Chandrasekar
- DOE Great Lakes Bioenergy Research Center, Michigan Technological University, Houghton, MI, USA
- Department of Chemical Engineering, Michigan Technological University, Houghton, MI, USA
| | - Leela Joshi
- DOE Great Lakes Bioenergy Research Center, Michigan Technological University, Houghton, MI, USA
- Department of Chemical Engineering, Michigan Technological University, Houghton, MI, USA
| | - Karleigh Krieg
- DOE Great Lakes Bioenergy Research Center, Michigan Technological University, Houghton, MI, USA
- Department of Chemical Engineering, Michigan Technological University, Houghton, MI, USA
| | - Sarvada Chipkar
- DOE Great Lakes Bioenergy Research Center, Michigan Technological University, Houghton, MI, USA
- Department of Chemical Engineering, Michigan Technological University, Houghton, MI, USA
| | - Emily Burke
- DOE Great Lakes Bioenergy Research Center, Michigan Technological University, Houghton, MI, USA
- Department of Chemical Engineering, Michigan Technological University, Houghton, MI, USA
| | - Derek J Debrauske
- DOE Great Lakes Bioenergy Research Center, Univ. of Wisconsin-Madison, Madison, USA
| | - Kurt D Thelen
- DOE Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, MI, USA
| | - Trey K Sato
- DOE Great Lakes Bioenergy Research Center, Univ. of Wisconsin-Madison, Madison, USA
| | - Rebecca G Ong
- DOE Great Lakes Bioenergy Research Center, Michigan Technological University, Houghton, MI, USA.
- Department of Chemical Engineering, Michigan Technological University, Houghton, MI, USA.
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Chundawat SPS, Pal RK, Zhao C, Campbell T, Teymouri F, Videto J, Nielson C, Wieferich B, Sousa L, Dale BE, Balan V, Chipkar S, Aguado J, Burke E, Ong RG. Ammonia Fiber Expansion (AFEX) Pretreatment of Lignocellulosic Biomass. J Vis Exp 2020. [PMID: 32364543 DOI: 10.3791/57488] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Lignocellulosic materials are plant-derived feedstocks, such as crop residues (e.g., corn stover, rice straw, and sugar cane bagasse) and purpose-grown energy crops (e.g., miscanthus, and switchgrass) that are available in large quantities to produce biofuels, biochemicals, and animal feed. Plant polysaccharides (i.e., cellulose, hemicellulose, and pectin) embedded within cell walls are highly recalcitrant towards conversion into useful products. Ammonia fiber expansion (AFEX) is a thermochemical pretreatment that increases accessibility of polysaccharides to enzymes for hydrolysis into fermentable sugars. These released sugars can be converted into fuels and chemicals in a biorefinery. Here, we describe a laboratory-scale batch AFEX process to produce pretreated biomass on the gram-scale without any ammonia recycling. The laboratory-scale process can be used to identify optimal pretreatment conditions (e.g., ammonia loading, water loading, biomass loading, temperature, pressure, residence time, etc.) and generates sufficient quantities of pretreated samples for detailed physicochemical characterization and enzymatic/microbial analysis. The yield of fermentable sugars from enzymatic hydrolysis of corn stover pretreated using the laboratory-scale AFEX process is comparable to pilot-scale AFEX process under similar pretreatment conditions. This paper is intended to provide a detailed standard operating procedure for the safe and consistent operation of laboratory-scale reactors for performing AFEX pretreatment of lignocellulosic biomass.
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Affiliation(s)
- Shishir P S Chundawat
- Department of Chemical and Biochemical Engineering, Rutgers-State University of New Jersey;
| | - Ramendra K Pal
- Department of Chemical and Biochemical Engineering, Rutgers-State University of New Jersey
| | - Chao Zhao
- Department of Chemical and Biochemical Engineering, Rutgers-State University of New Jersey
| | | | | | | | | | - Bradley Wieferich
- Department of Chemical Engineering and Materials Science, Michigan State University
| | - Leonardo Sousa
- Department of Chemical Engineering and Materials Science, Michigan State University
| | - Bruce E Dale
- Department of Chemical Engineering and Materials Science, Michigan State University
| | - Venkatesh Balan
- Engineering Technology Department, Biotechnology Program, College of Technology, University of Houston;
| | - Sarvada Chipkar
- Department of Chemical Engineering, Michigan Technological University
| | - Jacob Aguado
- Department of Chemical Engineering, Michigan Technological University
| | - Emily Burke
- Department of Chemical Engineering, Michigan Technological University
| | - Rebecca G Ong
- Department of Chemical Engineering, Michigan Technological University;
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Williams DL, Crowe JD, Ong RG, Hodge DB. Water sorption in pretreated grasses as a predictor of enzymatic hydrolysis yields. Bioresour Technol 2017; 245:242-249. [PMID: 28892697 DOI: 10.1016/j.biortech.2017.08.200] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Revised: 08/29/2017] [Accepted: 08/30/2017] [Indexed: 05/05/2023]
Abstract
This work investigated the impact of two alkaline pretreatments, ammonia fiber expansion (AFEX) and alkaline hydrogen peroxide (AHP) delignification performed over a range of conditions on the properties of corn stover and switchgrass. Changes in feedstock properties resulting from pretreatment were subsequently compared to enzymatic hydrolysis yields to examine the relationship between enzymatic hydrolysis and cell wall properties. The pretreatments function to increase enzymatic hydrolysis yields through different mechanisms; AFEX pretreatment through lignin relocalization and some xylan solubilization and AHP primarily through lignin solubilization. An important outcome of this work demonstrated that while changes in lignin content in AHP-delignified biomass could be clearly correlated to improved response to hydrolysis, compositional changes alone in AFEX-pretreated biomass could not explain differences in hydrolysis yields. We determined the water retention value, which characterizes the association of water with the cell wall of the pretreated biomass, can be used to predict hydrolysis yields for all pretreated biomass within this study.
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Affiliation(s)
- Daniel L Williams
- Department of Chemical Engineering & Materials Science, Michigan State University, East Lansing, MI, USA; DOE Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, MI, USA
| | - Jacob D Crowe
- Department of Chemical Engineering & Materials Science, Michigan State University, East Lansing, MI, USA
| | - Rebecca G Ong
- Department of Chemical Engineering, Michigan Technological University, Houghton, MI, USA
| | - David B Hodge
- Department of Chemical Engineering & Materials Science, Michigan State University, East Lansing, MI, USA; DOE Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, MI, USA; Department Biosystems & Agricultural Engineering, Michigan State University, East Lansing, MI, USA; Division of Chemical Engineering. Luleå University of Technology, SE-971 87 Luleå, Sweden.
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Crowe JD, Feringa N, Pattathil S, Merritt B, Foster C, Dines D, Ong RG, Hodge DB. Identification of developmental stage and anatomical fraction contributions to cell wall recalcitrance in switchgrass. Biotechnol Biofuels 2017; 10:184. [PMID: 28725264 PMCID: PMC5512841 DOI: 10.1186/s13068-017-0870-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 07/06/2017] [Indexed: 05/08/2023]
Abstract
BACKGROUND Heterogeneity within herbaceous biomass can present important challenges for processing feedstocks to cellulosic biofuels. Alterations to cell wall composition and organization during plant growth represent major contributions to heterogeneity within a single species or cultivar. To address this challenge, the focus of this study was to characterize the relationship between composition and properties of the plant cell wall and cell wall response to deconstruction by NaOH pretreatment and enzymatic hydrolysis for anatomical fractions (stem internodes, leaf sheaths, and leaf blades) within switchgrass at various tissue maturities as assessed by differing internode. RESULTS Substantial differences in both cell wall composition and response to deconstruction were observed as a function of anatomical fraction and tissue maturity. Notably, lignin content increased with tissue maturity concurrently with decreasing ferulate content across all three anatomical fractions. Stem internodes exhibited the highest lignin content as well as the lowest hydrolysis yields, which were inversely correlated to lignin content. Confocal microscopy was used to demonstrate that removal of cell wall aromatics (i.e., lignins and hydroxycinnamates) by NaOH pretreatment was non-uniform across diverse cell types. Non-cellulosic polysaccharides were linked to differences in cell wall response to deconstruction in lower lignin fractions. Specifically, leaf sheath and leaf blade were found to have higher contents of substituted glucuronoarabinoxylans and pectic polysaccharides. Glycome profiling demonstrated that xylan and pectic polysaccharide extractability varied with stem internode maturity, with more mature internodes requiring harsher chemical extractions to remove comparable glycan abundances relative to less mature internodes. While enzymatic hydrolysis was performed on extractives-free biomass, extractible sugars (i.e., starch and sucrose) comprised a significant portion of total dry weight particularly in stem internodes, and may provide an opportunity for recovery during processing. CONCLUSIONS Cell wall structural differences within a single plant can play a significant role in feedstock properties and have the potential to be exploited for improving biomass processability during a biorefining process. The results from this work demonstrate that cell wall lignin content, while generally exhibiting a negative correlation with enzymatic hydrolysis yields, is not the sole contributor to cell wall recalcitrance across diverse anatomical fractions within switchgrass.
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Affiliation(s)
- Jacob D. Crowe
- Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, MI USA
| | - Nicholas Feringa
- Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, MI USA
| | - Sivakumar Pattathil
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA USA
- Bioenergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN USA
| | - Brian Merritt
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA USA
| | - Cliff Foster
- DOE-Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, MI USA
| | - Dayna Dines
- DOE-Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, MI USA
| | - Rebecca G. Ong
- Department of Chemical Engineering, Michigan Technological University, Houghton, MI USA
| | - David B. Hodge
- Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, MI USA
- DOE-Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, MI USA
- Department of Biosystems & Agricultural Engineering, Michigan State University, East Lansing, MI USA
- Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, Luleå, Sweden
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10
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Dale BE, Anderson JE, Brown RC, Csonka S, Dale VH, Herwick G, Jackson RD, Jordan N, Kaffka S, Kline KL, Lynd LR, Malmstrom C, Ong RG, Richard TL, Taylor C, Wang MQ. Take a closer look: biofuels can support environmental, economic and social goals. Environ Sci Technol 2014; 48:7200-3. [PMID: 24934084 DOI: 10.1021/es5025433] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Affiliation(s)
- Bruce E Dale
- Michigan State University , East Lansing, Michigan 48824, United States
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Shao Q, Cheng C, Ong RG, Zhu L, Zhao C. Hydrogen peroxide presoaking of bamboo prior to AFEX pretreatment and impact on enzymatic conversion to fermentable sugars. Bioresour Technol 2013; 142:26-31. [PMID: 23732919 DOI: 10.1016/j.biortech.2013.05.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Revised: 05/01/2013] [Accepted: 05/04/2013] [Indexed: 06/02/2023]
Abstract
Bamboo is a fast growing plant found worldwide that has high potential as an energy crop. This project evaluated the effectiveness of AFEX pretreatment for converting moso bamboo (Phyllostachys heterocycla var. pubescens) to fermentable sugars, both with and without pre-soaking in hydrogen peroxide. Pretreatment conditions including temperature, water loading, residence time, ammonia loading, and hydrogen peroxide loadings were varied to maximize hydrolysis yields. The optimal conditions for AFEX were 150°C, 0.8 or 2.0 (w/w) water loading, 10-30 min residence time, and 2.0-5.0 (w/w) ammonia loading. The optimal conditions for H-AFEX were same AFEX conditions with 0.7-1.9 (w/w) 30% (wt) hydrogen peroxide solutions loading. Using 15 FPU/g glucan cellulase and under optimal conditions, AFEX pretreatment achieved a theoretical sugars yield of 64.8-72.7% and addition of hydrogen peroxide presoaking increased the yield to 83.4-92.1%. It is about 5-fold and 7-fold increase in sugars yield for AFEX-treated and H-AFEX-treated bamboo respectively.
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Affiliation(s)
- Qianjun Shao
- School of Engineering, Zhejiang A&F University, Linan, Zhejiang 311300, China.
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Dale BE, Ong RG. Energy, wealth, and human development: Why and how biomass pretreatment research must improve. Biotechnol Prog 2012; 28:893-8. [DOI: 10.1002/btpr.1575] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Revised: 06/12/2012] [Indexed: 11/11/2022]
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Abstract
OBJECTIVES To evaluate the bone density in the mandibles of young Australian adults of Mongoloid and Caucasoid descent. METHODS A panoramic radiograph (Orthophos C, Siemens AG, Bensheim, Germany) was obtained of 79 dental students from the School of Oral Health Sciences, The University of Western Australia. Exposure factors were varied for males and females. The films were automatically processed in a single batch and the optical density measured blindly at two locations by two examiners. The optical density was compared by race and sex to detect bone density differences. Individual lifestyle habits (exercise, alcohol consumption, smoking and diet) was recorded in a self-administered questionnaire. Multiple regression analysis was used to analyse the effects of physical, environmental and medical characteristics. RESULTS The Mongoloid subjects were found to have approximately 20% higher bone density at the angle of mandible than Caucasoid subjects (P = 0.0094 for males, P = 0.0004 for females). CONCLUSION Race is the most important variable associated with bone density. Mongoloid subjects should be given a higher exposure for panoramic radiography than that normally used for Caucasoid subjects.
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Affiliation(s)
- R G Ong
- Department of Oral Radiology, Perth Dental Hospital, Western Australia
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