Average amounts of different wheat bran components added back to the acid-treated bran included in the immobilization of <i>Alcaligenes aquatilis</i> strain F8.

<p>CMC: sodium carboxymethylcellulose</p><p>CVs: composite vitamins</p><p>Cellulose consisted of xylan and CMC; CVs were a mixture of B₁, B₂, B₃, B₆, B₉, E, and biotin.</p><p>^aunit: g</p><p>^bunit: mg</p><p>Average amounts of different wheat bran components added back to the acid-treated bran included in the immobilization of <i>Alcaligenes aquatilis</i> strain F8.</p

Cellulase activities, lipid production and cell growth of A2-E, A2-2, B11-C2, D1-B1 and D1-2(3).

<p>Incubation for cellulase activity measurement was conducted under submerged (SmF) conditions using wheat straw as substrate for 4 days. Lipid production and cell growth of transformants were determined under both submerged and solid-state conditions.</p>+<p>The control transformant introduced with the negative vector pPTRI without cellulase expression cassette.</p>++<p>The wild-type <i>A. oryzae</i> A-4.</p><p>*Submerged fermentation from wheat straw after 4 days.</p><p>**Solid state fermentation from wheat straw and bran mixture after 4 days.</p><p>***Loss in dry matter (LDM).</p><p>One-way ANOVA is used to test for differences: a, b means <i>p</i><0.05; A, B, C, D means <i>p</i><0.05; Values in brackets are standard errors.</p><p>Cellulase activities, lipid production and cell growth of A2-E, A2-2, B11-C2, D1-B1 and D1-2(3).</p

Neighbor-joining phylogenetic tree for <i>Alcaligenes aquatilis</i> strain F8 and related species based on 16S rDNA sequences.

<p>Bootstrap values (percentages of 1,000 replications) are shown at the branch points. Scale bar = 0.01 substitutions per nucleotide position (evolutionary distance).</p

Fabrication of Flexible Thermoplastic Polyurethane/Coal Hydrogasification Semi-coke Composites with Low rGO Content for High-Performance Microwave Absorption

Semi-coke (SC), a residue of coal hydrogasification, is recycled and incorporated into thermoplastic polyurethane (TPU) to create composites for microwave absorption (MA). Herein, we developed porous reduced SC (rSC)–reduced graphene oxide (rGO) hybrids (SGHs) via in situ reduction of a preoxidized SC (oSC) and graphene oxide (GO) mixture. Low-content GO was introduced to considerably improve the dielectric properties of SGHs while decreasing the production cost. Then, a solution blending technique was applied to develop microwave absorbers using TPU as the matrix. The obtained TPU/SGH5 composite with a feed ratio of 5:1 (oSC:GO) showed an optimum reflection loss of −48.81 dB at a thickness of 2.5 mm and an effective absorption bandwidth of 4.30 GHz (7.74–12.04 GHz) in 2–18 GHz. However, the MA property of the obtained composites with the same amount of rSC or rGO alone was not comparable to that of the TPU/SGH5 composite. The inherent magnetism, heteroatoms, and abundance of heterogeneous surfaces of rSC and the considerable dielectric loss of rGO worked together to improve the MA performance of TPU/SGH composites. This study offers an easy and effective technical method for producing high-performance microwave absorbers with a low rGO content, illuminating the path toward achieving sustainable development by converting waste into wealth

Engineering <i>Aspergillus oryzae</i> A-4 through the Chromosomal Insertion of Foreign Cellulase Expression Cassette to Improve Conversion of Cellulosic Biomass into Lipids

<div><p>A genetic modification scheme was designed for <i>Aspergillus oryzae</i> A-4, a natural cellulosic lipids producer, to enhance its lipid production from biomass by putting the spotlight on improving cellulase secretion. Four cellulase genes were separately expressed in A-4 under the control of <i>hlyA</i> promoter, with the help of the successful development of a chromosomal genetic manipulation system. Comparison of cellulase activities of PCR-positive transformants showed that these transformants integrated with <i>celA</i> gene and with <i>celC</i> gene had significantly (<i>p</i><0.05) higher average FPAase activities than those strains integrated with <i>celB</i> gene and with <i>celD</i> gene. Through the assessment of cellulosic lipids accumulating abilities, <i>celA</i> transformant A2-2 and <i>celC</i> transformant D1-B1 were isolated as promising candidates, which could yield 101%–133% and 35.22%–59.57% higher amount of lipids than the reference strain A-4 (WT) under submerged (SmF) conditions and solid-state (SSF) conditions, respectively. Variability in metabolism associated to the introduction of cellulase gene in A2-2 and D1-B1 was subsequently investigated. It was noted that cellulase expression repressed biomass formation but enhanced lipid accumulation; whereas the inhibitory effect on cell growth would be shielded during cellulosic lipids production owing to the essential role of cellulase in substrate utilization. Different metabolic profiles also existed between A2-2 and D1-B1, which could be attributed to not only different transgene but also biological impacts of different integration. Overall, both simultaneous saccharification and lipid accumulation were enhanced in A2-2 and D1-B1, resulting in efficient conversion of cellulose into lipids. A regulation of cellulase secretion in natural cellulosic lipids producers could be a possible strategy to enhance its lipid production from lignocellulosic biomass.</p></div

Characterization of Cellulase Secretion and Cre1-Mediated Carbon Source Repression in the Potential Lignocellulose-Degrading Strain <i>Trichoderma asperellum</i> T-1

<div><p><i>Trichoderma asperellum</i>, a traditional bio-control species, was demonstrated to be an excellent candidate for lignocellulose degradation in this work. Comparing to the representatively industrial strain of <i>Trichoderma reesei</i>QM6a, <i>T. asperellum</i> T-1 showed more robust growth, stronger spore production, faster secretion of lignocellulose-decomposing enzymes and better pH tolerance. The reducing sugar released by strain T-1 on the second day of fermentation was 87% higher than that of strain QM6a, although the maximum reducing sugar yield and the cellulase production persistence of the strain T-1 were lower. Our experiment found that the cellulase secretion was strongly inhibited by glucose, suggesting the existence of carbon source repression pathway in <i>T. asperellum</i> T-1. The inhibiting effect was enhanced with an increase in glucose concentration and was closely related to mycelium growth. SDS-PAGE and secondary mass-spectrum identification confirmed that the expression of endo-1,4-β-xylanase I in <i>T. asperellum</i> T-1 was down-regulated when glucose was added. The factor Cre1, which plays an important role in the down-regulation of the endo-1,4-β-xylanase I gene, was investigated by bioinformatics methods. The protein structure of Cre1, analyzed using multiple protein sequence alignment, indicates the existence of the Zn-fingers domain. Then, the binding sites of Cre1 on the endo-1,4-β-xylanase I gene promoter were further elucidated. This study is the first report about Cre1-mediated carbon repression in the bio-control strain <i>T. asperellum</i> T-1. All of the above results provided good references for better understanding <i>T. asperellum</i> T-1 and improving its application for lignocellulose degradation.</p></div

Preliminarily study of cellulase gene integration profiles in A2-2 and D1-B1, respectively.

<p>(A) Southern blot analysis. A part of <i>Amp</i>^r gene (0.7-kb) was amplified by PCR and used as the probe. (B) Primers designed for the insertion analysis of the target gene in A2-2 (<i>celA</i>) and D1-B1 (<i>celC</i>), and the theoretical results of PCR using the designed primers.</p

Cellulase production comparison of <i>T. asperellum</i> T-1 and <i>T. reesei</i> with wheat straw as carbon source, expressed as the concentration of reducing sugar released from the substrate by cellulase in the enzyme reaction system.

<p>(a) Filter paper activity (FPA) of <i>T. asperellum</i> T-1 (black circle) and <i>T. reesei</i> (diamond); (b) CMCase activity (endoglucanase activity) of <i>T. asperellum</i> T-1 (black circle) and <i>T. reesei</i> (diamond). Error bars denote standard deviations from the mean values of triplicate measurements (n = 3).</p

Enzyme production inhibition in <i>T. asperellum</i> T-1 by glucose addition at different growth periods, shown as the reducing sugar yield in the enzyme reaction system both in FPA (A) and CMCase (B).

<p>(A) FPA and (B) CMCase activity of <i>T. asperellum</i> T-1 with glucose added at different final concentrations (w/v) at 0 h (a), 36 h (b) and 60 h (c) of cultivation (0.5%: triangle up; 1%: square; 1.5%: diamond; 2.0%: hex; control: black circle). Error bars denote standard deviations from the mean values of triplicate measurements (n = 3).</p

Biomass and glucose consumption when different concentrations of glucose were used as the carbon sources.

<p>(Biomass: 0.5%: black triangle up; 1.0%: black square; 1.5%: black diamond; 2.0%: black hex; glucose consumption: 0.5%: dotted; 1.0%: short-short; 1.5%: dash-dot; 2.0%: long dash). Error bars denote standard deviations from the mean values of triplicate measurements (n = 3).</p