scholarly journals Macroalgae Derived Fungi Have High Abilities to Degrade Algal Polymers

2019 ◽  
Vol 8 (1) ◽  
pp. 52 ◽  
Author(s):  
Aleksandrina Patyshakuliyeva ◽  
Daniel L. Falkoski ◽  
Ad Wiebenga ◽  
Klaas Timmermans ◽  
Ronald P. de Vries

Marine fungi associated with macroalgae are an ecologically important group that have a strong potential for industrial applications. In this study, twenty-two marine fungi isolated from the brown seaweed Fucus sp. were examined for their abilities to produce algal and plant biomass degrading enzymes. Growth of these isolates on brown and green algal biomass revealed a good growth, but no preference for any specific algae. Based on the analysis of enzymatic activities, macroalgae derived fungi were able to produce algae specific and (hemi-)cellulose degrading enzymes both on algal and plant biomass. However, the production of algae specific activities was lower than the production of cellulases and xylanases. These data revealed the presence of different enzymatic approaches for the degradation of algal biomass by macroalgae derived fungi. In addition, the results of the present study indicate our poor understanding of the enzymes involved in algal biomass degradation and the mechanisms of algal carbon source utilization by marine derived fungi.

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Morten Schiøtt ◽  
Jacobus J Boomsma

The symbiotic partnership between leaf-cutting ants and fungal cultivars processes plant biomass via ant fecal fluid mixed with chewed plant substrate before fungal degradation. Here we present a full proteome of the fecal fluid of Acromyrmex leaf-cutting ants, showing that most proteins function as biomass degrading enzymes and that ca. 85% are produced by the fungus and ingested, but not digested, by the ants. Hydrogen peroxide producing oxidoreductases were remarkably common in the proteome, inspiring us to test a scenario in which hydrogen peroxide reacts with iron to form reactive oxygen radicals after which oxidized iron is reduced by other fecal-fluid enzymes. Our biochemical assays confirmed that these so-called Fenton reactions do indeed take place in special substrate pellets, presumably to degrade plant cell wall polymers. This implies that the symbiotic partnership manages a combination of oxidative and enzymatic biomass degradation, an achievement that surpasses current human bioconversion technology.


2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Jingen Li ◽  
Shuying Gu ◽  
Zhen Zhao ◽  
Bingchen Chen ◽  
Qian Liu ◽  
...  

Abstract Background Lignocellulosic biomass has long been recognized as a potential sustainable source for industrial applications. The costs associated with conversion of plant biomass to fermentable sugar represent a significant barrier to the production of cost-competitive biochemicals. Consolidated bioprocessing (CBP) is considered a potential breakthrough for achieving cost-efficient production of biomass-based fuels and commodity chemicals. During the degradation of cellulose, cellobiose (major end-product of cellulase activity) is catabolized by hydrolytic and phosphorolytic pathways in cellulolytic organisms. However, the details of the two intracellular cellobiose metabolism pathways in cellulolytic fungi remain to be uncovered. Results Using the engineered malic acid production fungal strain JG207, we demonstrated that the hydrolytic pathway by β-glucosidase and the phosphorolytic pathway by phosphorylase are both used for intracellular cellobiose metabolism in Myceliophthora thermophila, and the yield of malic acid can benefit from the energy advantages of phosphorolytic cleavage. There were obvious differences in regulation of the two cellobiose catabolic pathways depending on whether M. thermophila JG207 was grown on cellobiose or Avicel. Disruption of Mtcpp in strain JG207 led to decreased production of malic acid under cellobiose conditions, while expression levels of all three intracellular β-glucosidase genes were significantly up-regulated to rescue the impairment of the phosphorolytic pathway under Avicel conditions. When the flux of the hydrolytic pathway was reduced, we found that β-glucosidase encoded by bgl1 was the dominant enzyme in the hydrolytic pathway and deletion of bgl1 resulted in significant enhancement of protein secretion but reduction of malate production. Combining comprehensive manipulation of both cellobiose utilization pathways and enhancement of cellobiose uptake by overexpression of a cellobiose transporter, the final strain JG412Δbgl2Δbgl3 produced up to 101.2 g/L and 77.4 g/L malic acid from cellobiose and Avicel, respectively, which corresponded to respective yields of 1.35 g/g and 1.03 g/g, representing significant improvement over the starting strain JG207. Conclusions This is the first report of detailed investigation of intracellular cellobiose catabolism in cellulolytic fungus M. thermophila. These results provide insights that can be applied to industrial fungi for production of biofuels and biochemicals from cellobiose and cellulose.


2021 ◽  
Vol 11 (4) ◽  
pp. 1788
Author(s):  
Thanh-Tri Do ◽  
Binh-Nguyen Ong ◽  
Tuan-Loc Le ◽  
Thanh-Cong Nguyen ◽  
Bich-Huy Tran-Thi ◽  
...  

In the production of astaxanthin from Haematococcus pluvialis, the process of growing algal biomass in the vegetative green stage is an indispensable step in both suspended and immobilized cultivations. The green algal biomass is usually cultured in a suspension under a low light intensity. However, for astaxanthin accumulation, the microalgae need to be centrifuged and transferred to a new medium or culture system, a significant difficulty when upscaling astaxanthin production. In this research, a small-scale angled twin-layer porous substrate photobioreactor (TL-PSBR) was used to cultivate green stage biomass of H. pluvialis. Under low light intensities of 20–80 µmol photons m−2·s−1, algae in the biofilm consisted exclusively of non-motile vegetative cells (green palmella cells) after ten days of culturing. The optimal initial biomass density was 6.5 g·m−2, and the dry biomass productivity at a light intensity of 80 µmol photons m−2·s−1 was 6.5 g·m−2·d−1. The green stage biomass of H. pluvialis created in this small-scale angled TL-PSBR can be easily harvested and directly used as the source of material for the inoculation of a pilot-scale TL-PSBR for the production of astaxanthin.


Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2527
Author(s):  
Zahra Azzouz ◽  
Azzeddine Bettache ◽  
Nawel Boucherba ◽  
Alicia Prieto ◽  
Maria Jesus Martinez ◽  
...  

Plant biomass constitutes the main source of renewable carbon on the planet. Its valorization has traditionally been focused on the use of cellulose, although hemicellulose is the second most abundant group of polysaccharides on Earth. The main enzymes involved in plant biomass degradation are glycosyl hydrolases, and filamentous fungi are good producers of these enzymes. In this study, a new strain of Aspergillus niger was used for hemicellulase production under solid-state fermentation using wheat straw as single-carbon source. Physicochemical parameters for the production of an endoxylanase were optimized by using a One-Factor-at-a-Time (OFAT) approach and response surface methodology (RSM). Maximum xylanase yield after RSM optimization was increased 3-fold, and 1.41- fold purification was achieved after ultrafiltration and ion-exchange chromatography, with about 6.2% yield. The highest activity of the purified xylanase was observed at 50 °C and pH 6. The enzyme displayed high thermal and pH stability, with more than 90% residual activity between pH 3.0–9.0 and between 30–40 °C, after 24 h of incubation, with half-lives of 30 min at 50 and 60 °C. The enzyme was mostly active against wheat arabinoxylan, and its kinetic parameters were analyzed (Km = 26.06 mg·mL−1 and Vmax = 5.647 U·mg−1). Wheat straw xylan hydrolysis with the purified β-1,4 endoxylanase showed that it was able to release xylooligosaccharides, making it suitable for different applications in food technology.


REAKTOR ◽  
2014 ◽  
Vol 15 (1) ◽  
pp. 27
Author(s):  
M Mawardi ◽  
Edison Munaf ◽  
Soleh Kosela ◽  
Widayanti Wibowo

Karakteristik pemisahan ion Cr3+ dan Cr6+ dalam larutan melalui proses biosorpsi menggunakan biomassa alga hijau Spirogyra subsalsa dengan sistem batch telah diteliti. Dalam pelaksanaannya diawali dengan melakukan analisis kualitatif gugus fungsi dalam biomassa menggunakan instrumen FTIR, kemudian dipelajari karakteristik pengaruh variabel pH awal larutan, ukuran partikel biosorben, kecepatan pengadukan, pengaruh pemanasan biosorben, laju penyerapan, pengaruh konsentrasi larutan ion logam terhadap kapasitas serapan biomassa alga. Berdasarkan spektra spektroskopi FTIR dapat disimpulkan bahwa  biomassa alga hijau S. Subsalsa mengandung gugus-gugus karboksilat, amina, amida, amino, karbonil dan hidroksil, disamping adanya senyawa silikon, belerang dan fosfor. Hasil penelitian yang diperoleh  memperlihatkan bahwa kapasitas biosorpsi sangat dipengaruhi oleh pH larutan, waktu kontak dan konsentrasi awal larutan. Biosorpsi optimum kation Cr3+ terjadi pada pH 4,0 sedangkan ion Cr6+ terjadi pada pH 2,0 kemudian berkurang dejalan dengan naiknya pH larutan. Perhitungan dengan persamaan Isoterm Langmuir diperoleh data kapasitas serapan maksimum biomassa alga S. subsalsa untuk masing-masing ion Cr3+ dan Cr6+ adalah 1,82 mg (0,035 mmol) dan 1,51 mg (0,029 mmol) per gram biomassa kering. Kinetika biosorpsi berlangsung relatif cepat, dimana selama selang waktu 30 menit, masing-masing ion terserap sekitar 95,7%; dan 86,5%. Daya serap biomassa juga dipengaruhi kecepatan pengadukan, sedangkan faktor ukuran partikel dan pemanasan biosorben kurang mempengaruhi daya serap biomassa. Key Word : biosorpsi, spirogyra subsalsa, krom(III), krom(VI), sistem batchAbstract Separation of Ion Chromium(III) and Chromium(IV) In Solution Using Green Algae Biomass Spirogyra subsalsa as Biosorbent. The characteristics of Cr3+andCr6+ ion separation in solution through biosorption process using green algal biomass Spirogyrasubsalsa with batch systems have been investigated. The study began with aqualitative analysis of functional groups in biomass using FTIR instrument, then followed by a study of the characteristics of influences by several variables, such as: the initial pH of the solution,the size of biosorben particles, stirring speed, the effect of heating the biosorben, the rate of absorption, and the effect of metal ion concentration in solution on the absorption capacity of algal biomass. Based on FTIR spectroscopy spectra gave a conclusion that biomass of green algae S.subsalsa contains carboxylate groups, amine, amide, amino, carbonyl and hydroxyl, in addition to silicon, sulfur, and phosphorus compounds. The results showed that the biosorption capacity was strongly influenced by pH, contact time, and initial concentration ofthe solution. The optimum biosorption of Cr3+cation occurred at pH 4.0 while that of Cr6+ions occurred at pH 2.0 and then decreased with the increasing pH of solution. The calculation of Langmuir isotherm equation showed that the maximum absorption capacity of algal biomass S.subsalsa for Cr3+and Cr6+ ion respectively was 1.82mg (0.035 mmol) and 1.51 mg (0.029 mmol) pergram of dry biomass. The kinetics of biosorption took place relatively quick, in which during the 30minutes time interval, each ion was absorbed approximately 95.7%; and 86.5%. The absorptive capacity of biomass was also influenced by stirring speed, while the size of particles and heating biosorben gave lessinfluence to the absorption of biomass.


2012 ◽  
Vol 79 (4) ◽  
pp. 1316-1324 ◽  
Author(s):  
Joost van den Brink ◽  
Gonny C. J. van Muiswinkel ◽  
Bart Theelen ◽  
Sandra W. A. Hinz ◽  
Ronald P. de Vries

ABSTRACTRapid and efficient enzymatic degradation of plant biomass into fermentable sugars is a major challenge for the sustainable production of biochemicals and biofuels. Enzymes that are more thermostable (up to 70°C) use shorter reaction times for the complete saccharification of plant polysaccharides compared to hydrolytic enzymes of mesophilic fungi such asTrichodermaandAspergillusspecies. The genusMyceliophthoracontains four thermophilic fungi producing industrially relevant thermostable enzymes. Within this genus, isolates belonging toM. heterothallicawere recently separated from the well-described speciesM. thermophila. We evaluate here the potential ofM. heterothallicaisolates to produce efficient enzyme mixtures for biomass degradation. Compared to the other thermophilicMyceliophthoraspecies, isolates belonging toM. heterothallicaandM. thermophilagrew faster on pretreated spruce, wheat straw, and giant reed. According to their protein profiles andin vitroassays after growth on wheat straw, (hemi-)cellulolytic activities differed strongly betweenM. thermophilaandM. heterothallicaisolates. Compared toM. thermophila,M. heterothallicaisolates were better in releasing sugars from mildly pretreated wheat straw (with 5% HCl) with a high content of xylan. The high levels of residual xylobiose revealed that enzyme mixtures ofMyceliophthoraspecies lack sufficient β-xylosidase activity. Sexual crossing of twoM. heterothallicashowed that progenies had a large genetic and physiological diversity. In the future, this will allow further improvement of the plant biomass-degrading enzyme mixtures ofM. heterothallica.


2017 ◽  
Author(s):  
Chenlu Zhang ◽  
Ligia Acosta-Sampson ◽  
Vivian Yaci Yu ◽  
Jamie H. D. Cate

AbstractThe economic production of cellulosic biofuel requires efficient and full utilization of all abundant carbohydrates naturally released from plant biomass by enzyme cocktails. Recently, we reconstituted the Neurospora crassa xylodextrin transport and consumption system in Saccharomyces cerevisiae, enabling growth of yeast on xylodextrins aerobically. However, the consumption rate of xylodextrin requires improvement for industrial applications, including consumption in anaerobic conditions. As a first step in this improvement, we report analysis of orthologues of the N. crassa transporters CDT-1 and CDT-2. Transporter ST16 from Trichoderma virens enables faster aerobic growth of S. cerevisiae on xylodextrins compared to CDT-2. ST16 is a xylodextrin-specific transporter, and the xylobiose transport activity of ST16 is not inhibited by cellobiose. Other transporters identified in the screen also enable growth on xylodextrins including xylotriose. Taken together, these results indicate that multiple transporters might prove useful to improve xylodextrin utilization in S. cerevisiae. Efforts to use directed evolution to improve ST16 from a chromosomally-integrated copy were not successful, due to background growth of yeast on other carbon sources present in the selection medium. Future experiments will require increasing the baseline growth rate of the yeast population on xylodextrins, to ensure that the selective pressure exerted on xylodextrin transport can lead to isolation of improved xylodextrin transporters.


2021 ◽  
Author(s):  
Bashar Amer ◽  
Ramu Kakumanu ◽  
yangtian not provided ◽  
Aymerick Eudes ◽  
Edward EK Baidoo

Cell-wall-bound (CWB) aromatics such as ferulate and p-coumarate play important physiological roles in plant development and response to stresses. Their presence also poses some challenges and opportunities during processing of plant biomass in various agro-industrial applications. To this end, we have developed a robust high-throughput reversed-phase liquid chromatography mass spectrometry method for quantifying CWB phenolic compounds. The method showed excellent linearity (R2 = ≥0.999) and intraday retention time repeatability (≤ 0.31 %RSD) for ferulate and p-coumarate. The limits of detection and quantitation for these analytes were ≤ 39 nM and 130 nM, respectively. Furthermore, there was very little effect of the CWB sample matrix on the retention times of the analytes and analyte percent recoveries from the CWB sample matrix was ≥83.91%.


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