Hydrolysis of Corn Stover by Talaromyces cellulolyticus Enzymes: Evaluation of the Residual Enzymes Activities Through the Process

Optimization of Wheat Straw Conversion into Microbial Lipids by Lipomyces tetrasporus DSM 70314 from Bench to Pilot Scale

Microbial lipids are renewable platforms for several applications including biofuels, green chemicals, and nutraceuticals that can be produced from several residual carbon sources. Lignocellulosic biomasses are abundant raw materials for the production of second-generation sugars with conversion yields depending on the quality of the hydrolysates and the metabolic efficiency of the microorganisms. In the present work, wheat straw pre-treated by steam explosion and enzymatically hydrolysed was converted into microbial lipids by Lipomyces tetrasporus DSM 70314. The preliminary optimization of the enzymatic hydrolysis was performed at the bench scale through the response surface methodology (RSM). The fermentation medium and set-up were optimized in terms of the nitrogen (N) source and carbon-to-nitrogen (C/N) ratio yielding to the selection of soy flour as a N source and C/N ratio of 160. The bench scale settings were scaled-up and further optimized at the 10 L-scale and finally at the 50 L pilot scale bioreactor. Process optimization also included oxygen supply strategies. Under optimized conditions, a lipid concentration of 14.8 gL−1 was achieved corresponding to a 23.1% w/w lipid yield and 67.4% w/w lipid cell content. Oleic acid was the most abundant fatty acid with a percentage of 57%. The overall process mass balance was assessed for the production of biodiesel from wheat straw.

Humification process enhancement through relative abundance promotion of Talaromyces and Coprinopsis by inoculated Phanerochaete chrysosporium during the secondary fermentation of composting

To explore the mechanism of Phanerochaete chrysosporium (P. chrysosporium) inoculation driving the humification process of maize straw composting, the treatments without P. chrysosporium inoculation (T1) and that with P. chrysosporium inoculation (T2) were carried out separately during the secondary fermentation of the co-composting of maize straw and rapeseed cake. The key microorganisms were determined by evaluating the succession of the fungal community and its relationship with humification process parameters. The results showed that P. chrysosporium inoculation (T2) reduced fungal diversity but increased the relative abundance of Coprinopsis and Talaromyces. At the end of the composting (day 36), the relative abundance of Talaromyces and Coprinopsis in T2 increased by 1223.7% and 30.2%, respectively, compared with T1. Combined CCA and SEMs analyses demonstrated the microbially driven mechanisms that enhance the humification process of composting, that is, P. chrysosporium inoculation promoted lignin continuous degradation by promoting the relative abundance of Talaromyces and Coprinopsis during the secondary fermentation of composting; meanwhile, P. Chrysosporium inoculation further intensified the biological process of humification in composting.

Recombinant Family 1 Carbohydrate-Binding Modules Derived From Fungal Cellulase Enhance Enzymatic Degradation of Lignocellulose as Novel Effective Accessory Protein

Fungal cellulases usually contain a family 1 carbohydrate-binding module (CBM1), and its role was considered to recognize the substrate specifically. This study testified that the CBM1s derived from cellobiohydrolase I of Trichoderma reesei, Penicillium oxalicum, and Penicillium funiculosum could be used as an effective accessory protein in cellulase cocktails to enhance the saccharification of lignocellulose, and its enhancement effect was significantly superior to some reported accessory proteins, such as bovine serum albumin (BSA). The promoting effects of the CBM1s were related to not only the CBM1 sources and protein dosages, but also the substrate characteristics and solid consistency during enzymatic hydrolysis. The adsorption capacity of the CBM1s, the adsorption kinetic of TrCBM from T. reesei and cellobiohydrolase, endoglucanase, and β-glucosidase from P. oxalicum, and the effect of adding TrCBM on enzyme activities of free cellulases in the hydrolysis system were investigated, and the binding conformations and affinities of CBM1s to cellulose and lignin were predicted by molecular docking. It was speculated that the higher affinity of the CBM1s to lignin than cellulases could potentially enable the CBM1s to displace cellulase adsorbed on lignin or to preferentially adsorb onto lignin to avoid ineffective adsorption of cellulase onto lignin, which enhanced cellulase system efficiency during enzymatic hydrolysis of lignocellulose.

Talaromyces cellulolyticus as a promising candidate for biofilm construction and treatment of textile wastewater

Screening of microorganisms with broad-spectrum adaptability to extreme acid-base conditions and highperformance is essential for the construction of high-efficient biochemical wastewater treatment system. Herein, an acid-tolerant fungus isolated from acid medium was successfully identified through micromorphological observation and molecular characterization. The isolated fungus matched well with the filamentous fungus and was eventually identified as Talaromyces cellulolyticus. Considering the wide-range adaptability to pH condition (2.0-9.0), high cellulase activity (11.25 U mL^-1), ideal biofilm-forming property (17.87 mg cm^-3) on the surface of ceramsites, high tolerance to metal ions, and potential adsorption performance for aniline dyes, T. cellulolyticus issuitable for the construction of biofilm treatment system and treatment of textile wastewater based on the investigation of the removal efficiency of chemical oxygen demand and chromaticity of the synthetic textile wastewater. A promising candidate filamentous fungus for the treatment of textile wastewater was provided.

Cutaneotrichosporon oleaginosus: A Versatile Whole-Cell Biocatalyst for the Production of Single-Cell Oil from Agro-Industrial Wastes

Cutaneotrichosporon oleaginosus is an oleaginous yeast with several favourable qualities: It is fast growing, accumulates high amounts of lipids and has a very broad substrate spectrum. Its resistance to hydrolysis by-products makes it a promising biocatalyst for custom tailored microbial oils. C. oleaginosus can accumulate up to 60 wt.% of its biomass as lipids. This species is able to grow by using several compounds as a substrate, such as acetic acid, biodiesel-derived glycerol, N-acetylglucosamine, lignocellulosic hydrolysates, wastepaper and other agro-industrial wastes. This review is focused on state-of-the-art innovative and sustainable biorefinery schemes involving this promising yeast and second- and third-generation biomasses. Moreover, this review offers a comprehensive and updated summary of process strategies, biomass pretreatments and fermentation conditions for enhancing lipid production by C. oleaginosus as a whole-cell biocatalyst. Finally, an overview of the main industrial applications of single-cell oil is reported together with future perspectives.

Arundo donax Refining to Second Generation Bioethanol and Furfural

Biomass-derived sugars are platform molecules that can be converted into a variety of final products. Non-food, lignocellulosic feedstocks, such as agroforest residues and low inputs, high yield crops, are attractive bioresources for the production of second-generation sugars. Biorefining schemes based on the use of versatile technologies that operate at mild conditions contribute to the sustainability of the bio-based products. The present work describes the conversion of giant reed (Arundo donax), a non-food crop, to ethanol and furfural (FA). A sulphuric-acid-catalyzed steam explosion was used for the biomass pretreatment and fractionation. A hybrid process was optimized for the hydrolysis and fermentation (HSSF) of C6 sugars at high gravity conditions consisting of a biomass pre-liquefaction followed by simultaneous saccharification and fermentation with a step-wise temperature program and multiple inoculations. Hemicellulose derived xylose was dehydrated to furfural on the solid acid catalyst in biphasic media irradiated by microwave energy. The results indicate that the optimized HSSF process produced ethanol titers in the range 43–51 g/L depending on the enzymatic dosage, about 13–21 g/L higher than unoptimized conditions. An optimal liquefaction time before saccharification and fermentation tests (SSF) was 10 h by using 34 filter paper unit (FPU)/g glucan of Cellic® CTec3. C5 streams yielded 33.5% FA of the theoretical value after 10 min of microwave heating at 157 °C and a catalyst concentration of 14 meq per g of xylose.