Bioprocessing aspects of fuels and chemicals from biomass

Lee, Sun-Uk; Jung, Kwonsu; Park, Gwon Woo; Seo, Charles; Hong, Yeon Ki; Hong, Won Hi; Chang, Ho Nam

doi:10.1007/s11814-012-0080-6

Cited by 45 publications

(15 citation statements)

References 115 publications

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“…Before the pervaporation step, there is typically a filtration step to remove microbial cells from the fermentation broth, which are then recycled back to the fermentor. The filtration step is critical because pervaporation typically operates at a temperature much higher than that tolerated by the microbial cells [ 235 ]. A fermentation broth is in contact with one side of the membrane while a vacuum or gas purge is imposed on the other side.…”

Section: Microbial Fermentationmentioning

confidence: 99%

Current Challenges in Commercially Producing Biofuels from Lignocellulosic Biomass

2014

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Biofuels that are produced from biobased materials are a good alternative to petroleum based fuels. They offer several benefits to society and the environment. Producing second generation biofuels is even more challenging than producing first generation biofuels due the complexity of the biomass and issues related to producing, harvesting, and transporting less dense biomass to centralized biorefineries. In addition to this logistic challenge, other challenges with respect to processing steps in converting biomass to liquid transportation fuel like pretreatment, hydrolysis, microbial fermentation, and fuel separation still exist and are discussed in this review. The possible coproducts that could be produced in the biorefinery and their importance to reduce the processing cost of biofuel are discussed. About $1 billion was spent in the year 2012 by the government agencies in US to meet the mandate to replace 30% existing liquid transportation fuels by 2022 which is 36 billion gallons/year. Other countries in the world have set their own targets to replace petroleum fuel by biofuels. Because of the challenges listed in this review and lack of government policies to create the demand for biofuels, it may take more time for the lignocellulosic biofuels to hit the market place than previously projected.

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Section: Microbial Fermentationmentioning

confidence: 99%

Current Challenges in Commercially Producing Biofuels from Lignocellulosic Biomass

2014

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“…VFAs are the core intermediates of the so-called carboxylate platform [ 35 ], whose increasing importance relies on the multiple choices for VFAs conversion into compounds of industrial interest. Chemical processing of VFAs can yield bulk solvents/fuels such as ketones, aldehydes, and esters, with further steps yielding alcohols and alkanes [ 35 ], while biomaterials such as bioplastics are biologically produced using VFAs as preferred carbon sources (e.g., the polymers of the hydroxylated fatty acids between C4 and C8 [ 36 ]). While still in its infancy, the carboxylate platform has several advantages over the sugar and syngas platforms, with conversion efficiency the main one [ 37 ], and patented technologies applied for biomass conversion into carboxylate salts (the MixAlco™ process [ 38 ]).…”

Section: Introductionmentioning

confidence: 99%

Efficient molasses fermentation under high salinity by inocula of marine and terrestrial origin

Scoma

Coma

Kerckhof

et al. 2017

Biotechnol Biofuels

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BackgroundMolasses is a dense and saline by-product of the sugar agroindustry. Its high organic content potentially fuels a myriad of renewable products of industrial interest. However, the biotechnological exploitation of molasses is mainly hampered by the high concentration of salts, an issue that is nowadays tackled through dilution. In the present study, the performance of microbial communities derived from marine sediment was compared to that of communities from a terrestrial environment (anaerobic digester sludge). The aim was to test whether adaptation to salinity represented an advantage for fermenting molasses into renewable chemicals such as volatile fatty acids (VFAs) although high sugar concentrations are uncommon to marine sediment, contrary to anaerobic digesters.ResultsTerrestrial and marine microbial communities were enriched in consecutive batches at different initial pH values (pHi; either 6 or 7) and molasses dilutions (equivalent to organic loading rates (OLRs) of 1 or 5 gCOD L−1 d−1) to determine the best VFA production conditions. Marine communities were supplied with NaCl to maintain their native salinity. Due to molasses inherent salinity, terrestrial communities experienced conditions comparable to brackish or saline waters (20–47 mS cm−1), while marine conditions resembled brine waters (>47 mS cm−1). Enrichments at optimal conditions of OLR 5 gCOD L-1 d-1 and pHi 7 were transferred into packed-bed biofilm reactors operated continuously. The reactors were first operated at 5 gCOD L-1 d-1, which was later increased to OLR 10 gCOD L−1 d−1. Terrestrial and marine reactors had different gas production and community structures but identical, remarkably high VFA bioconversion yields (above 85%) which were obtained with conductivities up to 90 mS cm−1. COD-to-VFA conversion rates were comparable to the highest reported in literature while processing other organic leftovers at much lower salinities.ConclusionsAlthough salinity represents a major driver for microbial community structure, proper acclimation yielded highly efficient systems treating molasses, irrespective of the inoculum origin. Selection of equivalent pathways in communities derived from different environments suggests that culture conditions select for specific functionalities rather than microbial representatives. Mass balances, microbial community composition, and biochemical analysis indicate that biomass turnover rather than methanogenesis represents the main limitation to further increasing VFA production with molasses. This information is relevant to moving towards molasses fermentation to industrial application.Electronic supplementary materialThe online version of this article (doi:10.1186/s13068-017-0701-8) contains supplementary material, which is available to authorized users.

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“…Global warming and grain price hikes can be avoided by switching bio-fuel raw materials from grain and plant-oil sources to cellulosic biomass waste in the beginning. The extending volatile fatty acid-platform technology can be gradually moved to ordinary woody ligno-cellulosic biomass or energy crops in the future [41]. By recognizing its characteristic, biomass can be used it optimal.…”

Section: Resultsmentioning

confidence: 99%