Abstract:Cocos nucifera L. is a palm tree of paramount importance in the food and chemistry industries, although over 50% of its biomass is discarded as waste. The aim of the study is to investigate different pretreatments in to coconut husks (CH), based on acid, alkaline, ionic liquid (IL), and peroxidative, in order to produce fermentable sugars. Severity factors were calculated for pretreatments; values ranged from 0.3 to 1.7 for peroxide, from 0.01 to 1.4 for alkaline, from 1.4 to 2.8 for acid and from 2.0 to 3.0 f… Show more
“…High levels of extractives were found for the green coconut (average value of 15.3%), while for the other biomasses, low values were determined (average value <3.5%). These values are the following data found by other authors [24,25]. The three different primary and secondary hydrolysis methodologies for the content of polysaccharides and their respective monosaccharides were tested and figure 1 shows their results.…”
We investigated the effect of the reaction variable (time) on the extraction and hydrolysis process. The data showed that the methodologies of the National Renewable Energy Laboratory (NREL) must be adequate for each type of biomass and each regional reality. For the contents of total sugars in the biomass of green coconut, babassu and Brazil nut shell epicarp, the highest yields were found under different conditions from those proposed by NREL. In the total lignin content, the highest yields obtained were those proposed by the NREL method for all biomasses. In the content of extracts for coconut and babassu, the use of longer extraction time provided greater removal. For the chestnut fractions, shorter times led to higher yields. It is important to note that, with the optimized results, these biomasses can be used in the production of high value-added bioproducts with higher yields.
“…High levels of extractives were found for the green coconut (average value of 15.3%), while for the other biomasses, low values were determined (average value <3.5%). These values are the following data found by other authors [24,25]. The three different primary and secondary hydrolysis methodologies for the content of polysaccharides and their respective monosaccharides were tested and figure 1 shows their results.…”
We investigated the effect of the reaction variable (time) on the extraction and hydrolysis process. The data showed that the methodologies of the National Renewable Energy Laboratory (NREL) must be adequate for each type of biomass and each regional reality. For the contents of total sugars in the biomass of green coconut, babassu and Brazil nut shell epicarp, the highest yields were found under different conditions from those proposed by NREL. In the total lignin content, the highest yields obtained were those proposed by the NREL method for all biomasses. In the content of extracts for coconut and babassu, the use of longer extraction time provided greater removal. For the chestnut fractions, shorter times led to higher yields. It is important to note that, with the optimized results, these biomasses can be used in the production of high value-added bioproducts with higher yields.
“…2 ). Lignin removal from the shell and husk is comparable to that from rice husk using [TEA][HSO 4 ] and much higher than those reported from IL-pretreatment of coconut biomass (Table S2 ) 4 , 45 , 47 , 59 . Figure 2 Chemical composition of untreated and pretreated shell and husk pulps before and after pretreatment with [DMBA][HSO 4 ] ILs at optimum temperature and time conditions (Error bars represent standard deviations for three replicate measurements).…”
Coconut husks and shells are underutilised agricultural feedstocks in the bio-based industry. These biomass wastes have a higher lignin content than other woody biomass and have excellent potential as raw materials for the production of lignin-based materials. This work demonstrates the performance of a low-cost protic ionic liquid, N,N,N-dimethylbutylammonium hydrogen sulfate ([DMBA][HSO4]), for ionoSolv pretreatment of coconut husk and shell at 150 °C for 45–90 min and 170 °C for 15–60 min. Optimum pretreatment conditions were observed at 170 °C and 45 min for both feedstocks. At these conditions, [DMBA][HSO4] was able to remove almost 77 wt% of the lignin from the husk; leaving a cellulosic rich pulp behind, which released 82 % of the theoretical maximum glucose after enzymatic saccharification. The pretreated shell, by comparison, achieved 82 wt% lignin removal and 89 % glucose yield and these higher values could be attributed to the highly porous structure of coconut shell cell walls. The cleavage of the β-O-4 aryl ether linkages of lignin followed by extensive C–C condensation in the lignin at longer pretreatment times was shown by HSQC NMR analysis. This extensive condensation was evidenced by molecular weights > 10,000 g/mol exhibited by lignin precipitated after pretreatment at high temperature and long times. The high degree of lignin removal and high glucose release from both feedstocks demonstrate that [DMBA][HSO4] is an excellent ionic liquid for fractionation of very lignin-rich biomass.
“…Estudos realizados por Rambo et al (2020), visando a otimização de pré-tratamentos para a conversão de resíduos de coco em açúcares fermentáveis, alcançaram um teor de lignina na amostra in natura de, aproximadamente, 32,80%. Após a realização dos prétratamentos com H 2 O 2 3% (m/v), à 55 °C, durante 4h e NaOH 4% (m/v), à 70 °C, durante 3h, ambos na proporção biomassa/solvente de 1:20, este teor caiu para, cerca de, 20,80% e 14,39%, respectivamente.…”
Section: Pré-tratamentos Alcalinosunclassified
“…Entretanto, seu resíduo não possui um destino apreciável, uma vez que, cerca de, 85% do peso bruto se transforma em lixo, o que acaba por ocasionar problemas ambientais.Existem variadas formas de utilização do resíduo do coco que visam a minimização dos impactos ambientais, além de agregar valor a essa cadeia produtiva(NUNES et al, 2020), o que contribuiu para o aumento das pesquisas referentes a tratamentos eficientes envolvendo a digestão da celulose, remoção da hemicelulose, assim como a extração da lignina. O pré-tratamento da biomassa é fundamental em seu processo de transformação, uma vez que é responsável por facilitar a acessibilidade à biomassa lignocelulósica, ao quebrar as ligações complexas que envolvem os seus constituintes RAMBO et al, 2020),. NaClO 2(GONÇALVES et al, 2018), Ca(OH) 2(RABELO et al, 2011), dentre outros.…”
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