scholarly journals Heterotrophic and mixotrophic cultivation of Chlorella pyrenoidosa and the enzymatic hydrolysis of its biomass for the synthesis of third generation bioethanol

2014 ◽  
Author(s):  
Nisha Phour Dhull ◽  
Kshitiz Gupta ◽  
Sanjeev Kumar Soni
Keyword(s):  
Wheat Bran ◽  
Algal Biomass ◽  
Reducing Sugars ◽  
Carbon Sources ◽  
Chlorella Pyrenoidosa ◽  
Potential Candidate ◽  
Third Generation ◽  
Carbon Utilization ◽  
Enzyme Cocktail ◽  
Hydrolysis Of

The present study has been carried out with a view of evaluating a green alga Chlorella pyrenoidosa as a potential candidate for the production of reducing sugars using an enzyme cocktail of multiple carbohydrates produced on site for the fermentation into bioethanol. The ability of C. pyrenoidosa to grow similarly fast on different carbon sources and light has been studied in Fog’s medium in heterotrophic and mixotrophic cultures. The high cells densities of mixotrophic cultures demonstrated that the growth-stimulating effects of light and carbon utilization were better as compared to the effects of glucose in heterotrophic condition. Maximum biomass yield of 1.2 g/l was achieved with 1% Glucose and 0.2% KNO3 after 7 days of incubation at 28oC. The algal biomass was steam pretreated and hydrolyzed by a cocktail of multiple carbohydrases produced by solid state culture of a laboratory isolate belonging to Aspergillus sp. on wheat bran exhibiting the yields of 86, 35, 74, 1947, 61, 17000 and 1388 IU/g dry wheat bran for CMCase, FPase, β-glucosidase, xylanase, mannanase, α-amylase and glucoamylase respectively. The enzyme cocktail worked well in the hydrolysis of algal biomass at 50oC and produced total reducing sugars amounting to 429 mg/g of dried biomass revealing carbohydrate conversion efficiency of 96% after 48 h of hydrolysis. The released sugars may be fermented using suitable yeast strains for the production of third generation bioethanol.

scholarly journals Heterotrophic and mixotrophic cultivation of Chlorella pyrenoidosa and the enzymatic hydrolysis of its biomass for the synthesis of third generation bioethanol

2014 ◽  
Author(s):  
Nisha Phour Dhull ◽  
Kshitiz Gupta ◽  
Sanjeev Kumar Soni
Keyword(s):  
Wheat Bran ◽  
Algal Biomass ◽  
Reducing Sugars ◽  
Carbon Sources ◽  
Chlorella Pyrenoidosa ◽  
Potential Candidate ◽  
Third Generation ◽  
Carbon Utilization ◽  
Enzyme Cocktail ◽  
Hydrolysis Of

The present study has been carried out with a view of evaluating a green alga Chlorella pyrenoidosa as a potential candidate for the production of reducing sugars using an enzyme cocktail of multiple carbohydrates produced on site for the fermentation into bioethanol. The ability of C. pyrenoidosa to grow similarly fast on different carbon sources and light has been studied in Fog’s medium in heterotrophic and mixotrophic cultures. The high cells densities of mixotrophic cultures demonstrated that the growth-stimulating effects of light and carbon utilization were better as compared to the effects of glucose in heterotrophic condition. Maximum biomass yield of 1.2 g/l was achieved with 1% Glucose and 0.2% KNO3 after 7 days of incubation at 28oC. The algal biomass was steam pretreated and hydrolyzed by a cocktail of multiple carbohydrases produced by solid state culture of a laboratory isolate belonging to Aspergillus sp. on wheat bran exhibiting the yields of 86, 35, 74, 1947, 61, 17000 and 1388 IU/g dry wheat bran for CMCase, FPase, β-glucosidase, xylanase, mannanase, α-amylase and glucoamylase respectively. The enzyme cocktail worked well in the hydrolysis of algal biomass at 50oC and produced total reducing sugars amounting to 429 mg/g of dried biomass revealing carbohydrate conversion efficiency of 96% after 48 h of hydrolysis. The released sugars may be fermented using suitable yeast strains for the production of third generation bioethanol.

Valorization of agro-industrial wastes to produce hydrolytic enzymes by fungal solid-state fermentation

2018 ◽  
Vol 37 (2) ◽  
pp. 149-156 ◽  
Author(s):  
C. Marzo ◽  
A.B. Díaz ◽  
I. Caro ◽  
A. Blandino
Keyword(s):  
Solid State ◽  
Solid State Fermentation ◽  
Reducing Sugars ◽  
Raw Materials ◽  
Hydrolytic Enzymes ◽  
Industrial Wastes ◽  
Added Value ◽  
Orange Peels ◽  
Enzyme Cocktail ◽  
Hydrolysis Of

Nowadays, significant amounts of agro-industrial wastes are discarded by industries; however, they represent interesting raw materials for the production of high-added value products. In this regard, orange peels (ORA) and exhausted sugar beet cossettes (ESBC) have turned out to be promising raw materials for hydrolytic enzymes production by solid state fermentation (SSF) and also a source of sugars which could be fermented to different high-added value products. The maximum activities of xylanase and exo-polygalacturonase (exo-PG) measured in the enzymatic extracts obtained after the SSF of ORA were 31,000 U·kg-1 and 17,600 U·kg-1, respectively; while for ESBC the maximum values reached were 35,000 U·kg-1 and 28,000 U·kg-1, respectively. The enzymatic extracts obtained in the SSF experiments were also employed for the hydrolysis of ORA and ESBC. Furthermore, it was found that extracts obtained from SSF of ORA, supplemented with commercial cellulase, were more efficient for the hydrolysis of ORA and ESBC than a commercial enzyme cocktail typically used for this purpose. In this case, maximum reducing sugars concentrations of 57 and 47 g·L-1 were measured after the enzymatic hydrolysis of ESBC and ORA, respectively.

scholarly journals Cultivation of micro-algae for Production of Biodiesel: An optimized Process

2016 ◽  
Vol 7 ◽  
Author(s):  
Abebe Girma Demissie ◽  
Bhaskarrao Chinthapalli ◽  
Shumet Tenaw ◽  
D. S. Vijaya Chitra
Keyword(s):  
Algal Biomass ◽  
Incubation Temperature ◽  
Carbon Sources ◽  
Nitrogen Sources ◽  
Biodiesel Production ◽  
Potential Candidate ◽  
Potential Source ◽  
Microalgae Biomass ◽  
Basal Media

<p>Microalgae are considered as one of the potential source of biodiesel for the future. The search to obtain the potential strains from the algal diversity capable of producing oil is critical for sustainable production of biodiesel. In the present study, microalgae biomass with oil/lipid accumulation capability and their morphological features was isolated from Lake Abaya and Chamo. The algal biomass was cultivated <em>in vitro</em> and media optimization for maximum biomass was done using different basal media, BG-11 medium, and Chu -10. In addition the various carbon sources, nitrogen sources, pH and temperature were considered in this study for optimization. Green algae <em>Oedogonium</em>, <em>Chlorella </em>and <em>Cladophora</em> species were observed to be dominant species and the maximum oil per dry algal biomass was found to be from <em>Oedogonium</em> sp. Thus from the present study for the cultivation of the selected algae, BG-11 medium supplemented with tryptone (0.2%) sucrose (2%) and pH- 6 with incubation temperature of 30<sup>0</sup>C was found to be suitable.  These results suggest that <em>Oedogonium</em> sp. has several desirable features that make it a potential candidate for biodiesel production.</p>

scholarly journals Integrated Hydrolysis of Mixed Agro-Waste for a Second Generation Biorefinery Using Nepenthes mirabilis Pod Digestive Fluids

Processes ◽  
2019 ◽  
Vol 7 (2) ◽  
pp. 64 ◽  
Author(s):  
Nkosikho Dlangamandla ◽  
Seteno Ntwampe ◽  
Justine Angadam ◽  
Elie Itoba-Tombo ◽  
Boredi Chidi ◽  
...  
Keyword(s):  
Second Generation ◽  
Reducing Sugars ◽  
Low Cost ◽  
Integrated System ◽  
Yard Waste ◽  
Innovative Methods ◽  
Enzyme Cocktail ◽  
Total Reducing Sugars ◽  
Apple Peels ◽  
Hydrolysis Of

To sustainably operate a biorefinery with a low cost input in a commercial setting, the hydrolysis of lignocellulosic biomass must be undertaken in a manner which will impart environmental tolerance while reducing fermenter inhibitors from the delignification process. The challenge lies with the highly recalcitrant lignin structure, which limits the conversion of the holocelluloses to fermentable total reducing sugars (TRS). Due to these challenges, sustainable and innovative methods to pre-treat biomass must be developed for delignocellulolytic operations. Herein, Nepenthes mirabilis digestive fluids shown to have ligninolytic, cellulolytic and xylanolytic activities were used as an enzyme cocktail to hydrolyse mixed agro-waste constituted by Citrus sinensis (orange), Malus domestica (apple) peels, cobs from Zea mays (maize) and Quercus robur (oak) yard waste. The digestive fluids contained carboxylesterases (529.41 ± 30.50 U/L), β-glucosidases (251.94 ± 11.48 U/L) and xylanases (36.09 ± 18.04 U/L), constituting an enzymatic cocktail with significant potential for the reduction in total residual phenolic compounds (TRPCs), while being appropriate for holocellulose hydrolysis. Furthermore, the maximum TRS obtainable was 310 ± 5.19 mg/L within 168 h, while the TRPCs were reduced from 6.25 ± 0.18 to 4.26 ± 0.09 mg/L, which was lower than that observed when conventional methods were used. Overall, N. mirabilis digestive fluids demonstrated an ability to support biocatalytic processes with minimised cellulases hydrolysis interference. Therefore, the digestive enzymes in N. mirabilis pods can be used in an integrated system for feedstock hydrolysis in a second generation biorefinery.

An evaluation of synergistic interactions between feruloyl esterases and xylanases during the hydrolysis of various pre-treated agricultural residues

2021 ◽  
Author(s):  
◽  
Lithalethu Mkabayi
Keyword(s):  
Enzymatic Hydrolysis ◽  
Reducing Sugars ◽  
Value Added ◽  
Agricultural Residues ◽  
Corn Cobs ◽  
Synergistic Interactions ◽  
Enzyme Cocktail ◽  
Enzyme Combination ◽  
Pre Treatment ◽  
Hydrolysis Of

Agricultural residues are readily available and inexpensive renewable resources that can be used as raw materials for the production of value-added chemicals. The application of enzymes to facilitate the degradation of agricultural residues has long been considered the most environmentally friendly strategy for converting this material into good quality value-added chemicals. However, agricultural residues are typically lignocellulosic in composition and recalcitrant to enzymatic hydrolysis. Due to this recalcitrant nature, the complete degradation of biomass residues requires the synergistic action of a broad range of enzymes. The development and optimisation of synergistic enzyme cocktails is an effective approach for achieving high hydrolysis efficiency of lignocellulosic biomass. The aim of the current study was to evaluate the synergistic interactions between two termite metagenome-derived feruloyl esterases (FAE6 and FAE5) and endo-xylanases for the production of hydroxycinnamic acids and xylo-oligosaccharides (XOS) from model substrates, and untreated and pre-treated agricultural residues. Firstly, the two fae genes were heterologously expressed in Escherichia coli, and the recombinant enzymes were purified to homogeneity. The biochemical properties of the purified recombinant FAEs and xylanases (XT6 and Xyn11) were then assessed to determine the factors which influenced their activities and to select suitable operating conditions for synergy studies. An optimal protein loading ratio of xylanases to FAEs required to maximise the release of both reducing sugar and ferulic acid (FA) was established using 0.5% (w/v) insoluble wheat arabinoxylan (a model substrate). The enzyme combination of 66% xylanase and 33% FAE (on a protein loading basis) produced the highest amounts of reducing sugars and FA. The enzyme combination of XT6 (GH10 xylanase) and FAE5 or FAE6 liberated the highest amount of FA while a combination of Xyn11 (GH11 xylanase) and FAE5 or FAE6 produced the highest reducing sugar content. The synergistic interactions which were established between the xylanases and FAEs were further investigated using agricultural residues (corn cobs, rice straw and sugarcane bagasse). The three substrates were subjected to hydrothermal and dilute acid pre-treatment prior to synergy studies. It is generally known that, during pre-treatment, many compounds can be produced which may influence enzymatic hydrolysis. The effects of these by-products were assessed and it was found that lignin and its degradation products were the most inhibitory to the FAEs. The optimised enzyme cocktail was then applied to 1% (w/v) of untreated and pre-treated substrates for the efficient production of XOS and hydroxycinnamic acids. A significant improvement in xylanase substrate degradation was observed, especially with the combination of 66% Xyn11 and 33% FAE6 which displayed an improvement in reducing sugars of approximately 1.9-fold and 3.4-fold for hydrothermal and acid pre-treated corn cobs (compared to when Xyn11 was used alone), respectively. The study demonstrated that pre-treatment substantially enhanced the enzymatic hydrolysis of corn cobs and rice straw. Analysis of the hydrolysate product profiles revealed that the optimised enzyme cocktail displayed great potential for releasing XOS with a low degree of polymerisation. In conclusion, this study provided significant insights into the mechanism of synergistic interactions between xylanases and metagenome-derived FAEs during the hydrolysis of various substrates. The study also demonstrated that optimised enzyme cocktails combined with low severity pre-treatment can facilitate the potential use of xylan-rich lignocellulosic biomass for the production of valuable products in the future.

Enhanced Hydrolysis of Cellulose to Reducing Sugars on Kaolinte Clay Activated by Mineral Acid

2021 ◽  
Author(s):  
Yuxiao Dong ◽  
Dongshen Tong ◽  
Laibin Ren ◽  
Xingtao Chen ◽  
Hao Zhang ◽  
...  
Keyword(s):  
Reducing Sugars ◽  
Mineral Acid ◽  
Hydrolysis Of Cellulose ◽  
Hydrolysis Of

Base-catalyzed Degradations of Carbohydrates. IX. β-Eliminations of 4-O-Substituted Hexopyranosiduronates

1975 ◽  
Vol 53 (14) ◽  
pp. 2182-2188 ◽  
Author(s):  
Gerald O. Aspinall ◽  
Thinnayam N. Krishnamurthy ◽  
Walter Mitura ◽  
Masuo Funabashi
Keyword(s):  
Acid Hydrolysis ◽  
Reducing Sugars ◽  
Model Compounds ◽  
Methyl Methyl ◽  
Hydrolysis Of

Two methylated disaccharides, methyl [methyl 4-O-(2,3,4,6-tetra-O-methyl-α-D-glucopyranosyl)-2,3-di-O-methyl-β-D-glucopyranosid]uronate (9) and methyl 6-O-(methyl 2,3,4-tri-O-methyl-α-D-galactopyranosyluronate)-2,3,4-tri-O-methyl-β-D-glucopyranoside (15) have been synthesized and used as model compounds for the study of the base-catalyzed β-elimination of 4-O-substituted hexopyranosiduronates without degradation of exposed reducing sugars and of the selective acid hydrolysis of hex-4-enopyranosiduronates.

scholarly journals Production of Feruloyl Esterase from Aspergillus niger by Solid-State Fermentation on Different Carbon Sources

2011 ◽  
Vol 2011 ◽  
pp. 1-4 ◽  
Author(s):  
Shiyi Ou ◽  
Jing Zhang ◽  
Yong Wang ◽  
Ning Zhang
Keyword(s):  
Carbon Source ◽  
Nitrogen Source ◽  
Wheat Bran ◽  
Cell Walls ◽  
Carbon Sources ◽  
Feruloyl Esterase ◽  
Plant Cell Walls ◽  
Optimal Conditions ◽  
Carbon And Nitrogen ◽  
Maize Bran

A mixture of wheat bran with maize bran as a carbon source and addition of (NH4)SO4 as nitrogen source was found to significantly increase production of feruloyl esterase (FAE) enzyme compared with wheat bran as a sole carbon and nitrogen source. The optimal conditions in conical flasks were carbon source (30 g) to water 1 : 1, maize bran to wheat bran 1 : 2, (NH4)SO4 1.2 g and MgSO4 70 mg. Under these conditions, FAE activity was 7.68 mU/g. The FAE activity on the mixed carbon sources showed, high activity against the plant cell walls contained in the cultures.

scholarly journals Sinorhizobium meliloti Mutants Lacking Phosphotransferase System Enzyme HPr or EIIA Are Altered in Diverse Processes, Including Carbon Metabolism, Cobalt Requirements, and Succinoglycan Production

2008 ◽  
Vol 190 (8) ◽  
pp. 2947-2956 ◽  
Author(s):  
Catalina Arango Pinedo ◽  
Ryan M. Bringhurst ◽  
Daniel J. Gage
Keyword(s):  
Carbon Metabolism ◽  
Sinorhizobium Meliloti ◽  
Carbon Sources ◽  
Deletion Mutants ◽  
Symbiotic Relationship ◽  
Wild Type ◽  
Phosphotransferase System ◽  
Carbon Utilization ◽  
Carbon Regulation ◽  
Extreme Sensitivity

ABSTRACT Sinorhizobium meliloti is a member of the Alphaproteobacteria that fixes nitrogen when it is in a symbiotic relationship. Genes for an incomplete phosphotransferase system (PTS) have been found in the genome of S. meliloti. The genes present code for Hpr and ManX (an EIIAMan-type enzyme). HPr and EIIA regulate carbon utilization in other bacteria. hpr and manX in-frame deletion mutants exhibited altered carbon metabolism and other phenotypes. Loss of HPr resulted in partial relief of succinate-mediated catabolite repression, extreme sensitivity to cobalt limitation, rapid die-off during stationary phase, and altered succinoglycan production. Loss of ManX decreased expression of melA-agp and lac, the operons needed for utilization of α- and β-galactosides, slowed growth on diverse carbon sources, and enhanced accumulation of high-molecular-weight succinoglycan. A strain with both hpr and manX deletions exhibited phenotypes similar to those of the strain with a single hpr deletion. Despite these strong phenotypes, deletion mutants exhibited wild-type nodulation and nitrogen fixation when they were inoculated onto Medicago sativa. The results show that HPr and ManX (EIIAMan) are involved in more than carbon regulation in S. meliloti and suggest that the phenotypes observed occur due to activity of HPr or one of its phosphorylated forms.

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