Bioethanol production from agarophyte red seaweed, Gelidium elegans, using a novel sample preparation method for analysing bioethanol content by gas chromatography

Hessami, Mohammad Javad; Cheng, Sit Foon; Ambati, Ranga Rao; Yin, Yeong Hui; Phang, Siew Moi

doi:10.1007/s13205-018-1549-8

Cited by 38 publications

(9 citation statements)

References 34 publications

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“…A significant amount of research has been conducted on bioethanol production from red seaweeds, of which sulphuric acid has been identified to be the most suitable reaction catalyst for the initial pre-treatment stage. This includes studies performed on Kappaphycus alvarezii [15,34] Gelidium amansii [35][36][37], Gracilaria verrucosa [38], Gracilaria tenuistipitata [36], Gelidium elegans [39] and Gracilariopsis chorda [36], where sequential two stage pretreatments (acid pre-treatment followed by enzyme hydrolysis) have been applied, subsequently followed by fermentation to bioethanol. A study by Nguyen et al [35] who identified optimal conditions (180 mM sulphuric acid at 121°C for 45 min at a solids loading content of 12% w/v) for liberating glucose (6.8 g L −1 ) and galactose (26.1 g L −1 ) from G. amansii included an additional detoxification step in order to remove HMF which had reached levels as high as 8.7 g L −1 as a result of the thermal acid pre-treatment.…”

Section: Investigation Of Pre-treatment Conditionsmentioning

confidence: 99%

Bioethanol Production from UK Seaweeds: Investigating Variable Pre-treatment and Enzyme Hydrolysis Parameters

2019

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This study describes the method development for bioethanol production from three species of seaweed. Laminaria digitata, Ulva lactuca and for the first time Dilsea carnosa were used as representatives of brown, green and red species of seaweed, respectively. Acid thermo-chemical and entirely aqueous (water) based pre-treatments were evaluated, using a range of sulphuric acid concentrations (0.125-2.5 M) and solids loading contents (5-25 % [w/v]; biomass: reactant) and different reaction times (5-30 min), with the aim of maximising the release of glucose following enzyme hydrolysis. A pre-treatment step for each of the three seaweeds was required and pre-treatment conditions were found to be specific to each seaweed species. Dilsea carnosa and U. lactuca were more suited with an aqueous (water-based) pre-treatment (yielding 125.0 and 360.0 mg of glucose/g of pretreated seaweed, respectively), yet interestingly non pre-treated D. carnosa yielded 106.4 g g −1 glucose. Laminaria digitata required a dilute acid thermo-chemical pre-treatment in order to liberate maximal glucose yields (218.9 mg glucose/g pre-treated seaweed). Fermentations with S. cerevisiae NCYC2592 of the generated hydrolysates gave ethanol yields of 5.4 g L −1 , 7.8 g L −1 and 3.2 g L −1 from D. carnosa, U. lactuca and L. digitata, respectively. This study highlighted that entirely aqueous based pretreatments are effective for seaweed biomass, yet bioethanol production alone may not make such bio-processes economically viable at large scale.

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Section: Investigation Of Pre-treatment Conditionsmentioning

confidence: 99%

Bioethanol Production from UK Seaweeds: Investigating Variable Pre-treatment and Enzyme Hydrolysis Parameters

2019

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“…In the present study, the ethanol production rate and fermentation e ciency of the acid hydrolysate (AH) were low, due to the presence of galactose as the main reducing sugar in the dilute acid hydrolysate, and the fact that ethanol yield from galactose is lower than glucose (Hong et al 2011;Hessami et al 2019). D-Galactose undergoes conversion via the Leloir pathway; basically, in this pathway, a ve-step enzymatic pathway converts D-Galactose to glucose-6-phosphate (Timson 2007).…”

Section: Discussionmentioning

confidence: 77%

Bioethanol production from defatted biomass of Nannochloropsis oculata microalgae grown under mixotrophic conditions

Fetyan

El-Sayed

Ibrahim

et al. 2021

Environ Sci Pollut Res

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Microalgal biomass is one of the most promising third-generation feedstocks for bioethanol production because it contains signi cantly reduced sugar amounts which, by separate hydrolysis and fermentation, can be used as a source for ethanol production. In this study, the defatted microalgal biomass of Nannochloropsis oculata (NNO-1 UTEX Culture LB 2164) was subjected to bioethanol production through acid digestion and enzymatic treatment before being fermented by Saccharomyces cerevisiae (NRRLY-2034). For acid hydrolysis (AH), the highest carbohydrate yield 252.84 mg/g DW was obtained with 5.0% (v/v) H 2 SO 4 at 121°C for 15 min for defatted biomass cultivated mixotrophically on SBAE with respect to 207.41 mg/g DW for defatted biomass cultivated autotrophically (control treatment), Whereas, the highest levels of reducing sugars was obtained With 4.0%(v/v) H 2 SO 4 157.47 ± 1.60 mg/g DW for defatted biomass cultivated mixotrophically in compared with 135.30 mg/g DW for the defatted control treatment. The combination of acid hydrolysis 2.0% (v/v) H 2 SO 4 followed by enzymatic treatment (AEH) increased the carbohydrate yields to 268.53 mg/g DW for defatted biomass cultivated mixotrophically on SBAE with respect to 177.73 mg/g DW for the defatted control treatment. However, the highest levels of reducing sugars were obtained with 3.0% (v/v) H 2 SO 4 followed by enzyme treatment gave 232.39 ± 1.77 for defatted biomass cultivated mixotrophically on SBAE and 150.75 mg/g DW for the defatted control treatment. The sugar composition of the polysaccharides showed that glucose was the principal polysaccharide sugar (60.7%-62.49%) of N. oculata defatted biomass. Fermentation of the hydrolysates by Saccharomyces cerevisiae for the acid pretreated defatted biomass samples gave ethanol yield of 0.86 g/l (0.062 g/g sugar consumed) for control and 1.17 g/l (0.069 g/g sugar consumed) for SBAE mixotrophic. Whereas, the maximum ethanol yield of 6.17 ± 0.47 g/l (0.26 ± 0.11 g/g sugar consumed) was obtained with samples from defatted biomass grown mixotrophically (SBAE mixotrophic) pretreated with acid coupled enzyme hydrolysis.

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Section: Discussionmentioning

confidence: 77%

Bioethanol production from defatted biomass of Nannochloropsis oculata microalgae grown under mixotrophic conditions

Fetyan¹,

El-Sayed

Ibrahim

et al. 2021

Preprint

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Microalgal biomass is one of the most promising third-generation feedstocks for bioethanol production because it contains significantly reduced sugar amounts which, by separate hydrolysis and fermentation, can be used as a source for ethanol production. In this study, the defatted microalgal biomass of Nannochloropsis oculata (NNO-1 UTEX Culture LB 2164) was subjected to bioethanol production through acid digestion and enzymatic treatment before being fermented by Saccharomyces cerevisiae (NRRLY-2034). For acid hydrolysis (AH), the highest carbohydrate yield 252.84 mg/g DW was obtained with 5.0% (v/v) H2SO4 at 121°C for 15 min for defatted biomass cultivated mixotrophically on SBAE with respect to 207.41 mg/g DW for defatted biomass cultivated autotrophically (control treatment), Whereas, the highest levels of reducing sugars was obtained With 4.0%(v/v) H2SO4 157.47 ± 1.60 mg/g DW for defatted biomass cultivated mixotrophically in compared with 135.30 mg/g DW for the defatted control treatment. The combination of acid hydrolysis 2.0% (v/v) H2SO4 followed by enzymatic treatment (AEH) increased the carbohydrate yields to 268.53 mg/g DW for defatted biomass cultivated mixotrophically on SBAE with respect to 177.73 mg/g DW for the defatted control treatment. However, the highest levels of reducing sugars were obtained with 3.0% (v/v) H2SO4 followed by enzyme treatment gave 232.39 ± 1.77 for defatted biomass cultivated mixotrophically on SBAE and 150.75 mg/g DW for the defatted control treatment. The sugar composition of the polysaccharides showed that glucose was the principal polysaccharide sugar (60.7%-62.49%) of N. oculata defatted biomass. Fermentation of the hydrolysates by Saccharomyces cerevisiae for the acid pretreated defatted biomass samples gave ethanol yield of 0.86 g/l (0.062 g/g sugar consumed) for control and 1.17 g/l (0.069 g/g sugar consumed) for SBAE mixotrophic. Whereas, the maximum ethanol yield of 6.17 ± 0.47 g/l (0.26 ± 0.11 g/g sugar consumed) was obtained with samples from defatted biomass grown mixotrophically (SBAE mixotrophic) pretreated with acid coupled enzyme hydrolysis.

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Bioethanol production from agarophyte red seaweed, Gelidium elegans, using a novel sample preparation method for analysing bioethanol content by gas chromatography

Cited by 38 publications

References 34 publications

Bioethanol Production from UK Seaweeds: Investigating Variable Pre-treatment and Enzyme Hydrolysis Parameters

Bioethanol Production from UK Seaweeds: Investigating Variable Pre-treatment and Enzyme Hydrolysis Parameters

Bioethanol production from defatted biomass of Nannochloropsis oculata microalgae grown under mixotrophic conditions

Bioethanol production from defatted biomass of Nannochloropsis oculata microalgae grown under mixotrophic conditions

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