Characterization of lignin-derived products from various lignocellulosics as treated by semi-flow hot-compressed water

To elucidate the decomposition behaviors of lignin from different taxonomic groups, five different lignocellulosics were treated with hot-compressed water (230 °C/10 MPa/15 min) to fractionate lignins into water-soluble portions, precipitates, and insoluble residues. The lignin-derived products in each fraction were characterized and compared. The delignification of monocotyledons [nipa palm (Nypa fruticans) frond, rice (Oryza sativa) straw, and corn (Zea mays) cob] was more extensive than that achieved for Japanese cedar (Cryptomeria japonica, gymnosperm) and Japanese beech (Fagus crenata, dicotyledon angiosperm). The water-soluble portions contained lignin monomers like coniferyl alcohol and phenolic acids, while the precipitates contained higher molecular weight lignin with high content of ether-type linkages. Lignin in the insoluble residues was rich in condensed-type structures. In all five lignocellulosics, ether-type linkages were preferentially cleaved, while condensed-type lignin showed resistance to hot-compressed water. In the monocotyledons, lignin–carbohydrate complexes were cleaved and gave lignins that had higher molecular weights than those eluted from the woods. These differences would facilitate the delignification in monocotyledons. Such information provides useful information for efficient utilization of various lignocellulosics

Comparative study on chemical composition of various biomass species

In this study, the chemical composition of 32 samples coming from 29 different biomass species including a gymnosperm, 2 dicotyledonous angiosperms, 17 monocotyledonous angiosperms and 9 algae species was successfully determined using an established method applicable to analyze various biomass species. The obtained data allowed a direct comparison of the biomass in their chemical composition. It was, thus, revealed that although the chemical composition differed from one species to another, and even from different parts of the same plants, similar trends were found in the composition of biomass species belonging to the same taxonomic group. Based on those results, it was clarified that the chemical composition of a biomass sample is related to its taxonomy. Therefore, typical chemical composition for each taxonomic group was proposed and the potential of each group for different biorefinery platforms could be defined

バイオリファイナリー原料としての種々バイオマスの化学組成に関する定量評価

京都大学0048新制・課程博士博士(エネルギー科学)甲第16964号エネ博第252号新制||エネ||53(附属図書館)29639京都大学大学院エネルギー科学研究科エネルギー社会・環境科学専攻(主査)教授 坂 志朗, 教授 東野 達, 准教授 河本 晴雄学位規則第4条第1項該当Doctor of Energy ScienceKyoto UniversityDA

Quantitative method applicable for various biomass species to determine their chemical composition

A quantitative method applicable for various biomass species to determine their chemical constituents was explored. The widely used wood analytical method was found to be not entirely applicable to different biomass species. It was then demonstrated that by incorporating protein and starch determinations, by ash-correcting the Klason lignin and holocellulose and also by protein-correcting Klason lignin and holocellulose of high protein content species, reliable summative results that enable comparison between different types of biomass materials were achieved. Thus, an analytical method with starch and protein determinations as well as ash and protein corrections was proposed for quantitative assay of chemical composition of various biomass species

Nipa Sap Can Be Both Carbon and Nutrient Source for Acetic Acid Production by <i>Moorella thermoacetica</i> (f. <i>Clostridium thermoaceticum</i>) and Reduced Minimal Media Supplements

Nipa sap is an excellent microbial nutrient and carbon source since it contains essential minerals and vitamins, in addition to sugars. In this study, nipa sap was successfully fermented to acetic acid by the industrially important Moorella thermoacetica without additional trace metals, without inorganics, or without yeast extract. Although microbial growth kinetics differed from one nutrient condition to another, acetic acid concentrations obtained without trace metals, without inorganics, and without yeast extract supplements were in the same range as that with full nutrient, confirming that nipa sap is a good nutrient source for M. thermoacetica. Fermentations in vials and fermenters showed comparable acetic acid production trends but acetic acid concentrations were higher in fermenters. Upon economic analysis, it was found that the most profitable nutrient condition was without yeast extract. It reduced the cost of culture medium from $1.7 to only$0.3/L, given that yeast extract costs $281/kg, while nipa sap can be available from$0.08/kg. Minimal medium instead of the traditional complex nutrient simplifies the process. This work also opens opportunities for profitable anaerobic co-digestion and co-fermentation of nipa sap with other biomass resources where nipa sap will serve as an inexpensive nutrient source and substrate

Fed-batch fermentation of nipa sap to acetic acid by Moorella thermoacetica (f. Clostridium thermoaceticum)

An efficient process for conversion of nipa sap to acetic acid was developed. Nipa sap was hydrolyzed with invertase and provided glucose as well as fructose as main sugars. Batch fermentation of glucose and fructose was inadequate with increased substrate concentration. By contrast, fed-batch technique on hydrolyzed nipa sap with high feeding rate drastically increased acetic acid concentration and productivity to be 42.6 g/L and 0.18 g/(L/h), respectively. All the sugars in hydrolyzed nipa sap were consumed, with acetic acid yield of 0.87 g/g sugar. Overall, nipa sap as hydrolyzed with invertase was efficiently fermented to acetic acid, which is a valuable chemical and a potential biorefinery intermediate

Two-step hydrolysis of rice (Oryza sativa) husk as treated by semi-flow hot-compressed water

Two-step hydrolysis of husk obtained from rice (Oryza sativa) was investigated as one of the monocotyledonous angiosperms under the semi-flow hot-compressed water treatment at 230 °C/10 MPa/15 min (1st stage) and 270 °C/10 MPa/30 min (2nd stage). Prior to the hot-compressed water treatment, cold-water extraction at 20 °C/10 MPa/30 min was performed. It was found that some inorganic constituents and free neutral sugars not being chemically bonded with the plant cell wall were recovered in the cold-water extracts. In the 1st stage, hemicelluloses and pectin were selectively hydrolyzed, as well as lignin being partially decomposed. In addition, protein was found to some extent to be hydrolyzed by the hot-compressed water treatment and various amino acids to form the protein of rice husk were identified. Hydrolysis of cellulose was, however, observed in the 2nd stage. Some additional decomposition of lignin and protein was revealed at this stage as well. In total, 96.1% of oven-dried extractives-free rice husk sample could be solubilized into cold and hot-compressed water. Various products in the water-soluble portion were primarily recovered as saccharides, which were partially isomerized and then dehydrated and fragmented. The 3.9% of residue after the treatment was composed mainly of lignin and a trace of silica

Sap from various palms as a renewable energy source for bioethanol production

Sap is a watery fluid that transports plant photosynthetic products towards various tissues to support growth. Tapping palms for their sap is reported to have originated from India approximately 4,000 years ago. Palm sap is rich in sugars with some inorganics and nutrients, which are attractive components for bioethanol production. Based on advances and current knowledge on the availability, collection, yield, and exploitation of various palm saps, this article evaluates their potential and sustainability as feedstocks for bioethanol production