Bioprocess and Biosystems Engineering最新文献

Glycolipids are a class of widely studied biosurfactants with excellent applicability in cosmetic and pharmaceutical formulations. This class of biosurfactants includes mannosylerythritol lipids (MELs), which have gained particular interest due to their moisturizing and healing activity for dry and damaged human skin, arising from conditions such as eczema. Traditionally, MELs have been produced by growing certain basidiomycetous yeasts on vegetable oils. However, oils are a comparatively expensive substrate, which negatively affects the economic performance of MEL production. In addition to this, vegetable oils significantly complicate the downstream processing required to produce a product with the required purity for most applications. To address these challenges, this study investigated MEL-A production exclusively from hydrophilic carbon sources by Ustilago maydis DSM 4500. By implementing a fed-batch production strategy, maximum MEL-A concentration of 0.87 g/L was achieved from glucose exclusively. Also, adding micronutrients (such as MnSO₄) to MEL-A production showed a 24.1% increase in the product titer, implying other metabolites are formed, favoring MEL production.

Encapsulating the enzyme in metal-organic frameworks (MOFs) is a convenient method to prepare MOF-enzyme biocomposite. In this study, Candida antarctica lipase B (CAL-B) was chosen to immobilize in Cu-BTC MOF under ultrasound irradiation. CAL-B was immobilized in Cu-BTC under ultrasound at 21 kHz and 11.4 W/cm² and incubation. 98% of CAL-B was immobilized in Cu-BTC with 99 U/mg activity (threefold more active than the free CAL-B). The prepared biocomposite was characterized using FT-IR, XRD, TGA, SEM, EDX, and BET. The thermal and solvent stability of CAL-B@Cu-BTC was investigated. It was found that at a temperature of 55 ℃, CAL-B@Cu-BTC maintains its activity even after 2 h of incubation. Furthermore, in the presence of 20% and 50% concentrations of MeCN, THF, and DMF, CAL-B@Cu-BTC was found to have an activity of over 80%. A prepared biocatalyst was used to synthesize 1,3,4,5-tetrasubstituted pyrazole derivatives (50-75%) in a one-pot vessel, by adding phenyl hydrazine hydrochlorides, benzaldehydes, and dimethyl acetylenedicarboxylate.

Microalgae, compared to macroalgae, exhibit advantages such as rapid growth rates, feasible large-scale cultivation, and high fucoxanthin content. Among these microalgae, Phaeodactylum tricornutum emerges as an optimal source for fucoxanthin production. This paper comprehensively reviews the research progress on fucoxanthin production using Phaeodactylum tricornutum from 2012 to 2022, offering detailed insights into various aspects, including strain selection, media optimization, nutritional requirements, lighting conditions, cell harvesting techniques, extraction solvents, extraction methodologies, as well as downstream separation and purification processes. Additionally, an economic analysis is performed to assess the costs of fucoxanthin production from Phaeodactylum tricornutum, with a comparative perspective to astaxanthin production from Haematococcus pluvialis. Lastly, this paper discusses the current challenges and future opportunities in this research field, serving as a valuable resource for researchers, producers, and industry managers seeking to further advance this domain.

To more greenly and efficiently utilize the abundant lignite resources and explore the microbial degradation and transformation potential of lignite for its environmentally friendly and resourceful utilization, Shengli lignite from the Hulunbuir region of Inner Mongolia, China, was selected as the research subject. Through the dilution plating method and streaking method, 31 native microorganisms were successfully isolated from the Shengli lignite, including 16 bacteria and 15 fungi. After microbial coal dissolution experiments, it was found that certain microorganisms have a significant dissolving effect on lignite, with some bacterial and fungal strains showing strong dissolution capabilities. In particular, the bacterium SH10 Lysinibacillus fusiformis and the fungus L1W Paecilomyces lilacinus demonstrated the best coal-dissolving abilities, with dissolution rates both reaching 60%. The products of microbial dissolution of lignite were analyzed using gas chromatography-mass spectrometry (GC-MS) technology, identifying a variety of small molecular organic compounds, including alkanes, alcohols, esters, and phenols. The results of this study provide a new perspective on the biodegradation of lignite and lay the foundation for the development of new lignite treatment and utilization technologies.

Endophytic fungi, as plant symbionts, produce an elaborate array of enzymes for efficient disintegration of lignocellulosic biomass into constituent monomeric sugars, making them novel source of lignocellulolytic CAZymes with immense potential in future biorefineries. The present study reports lignocellulolytic enzymes production potential of an endophytic halotolerant Penicillium oxalicum strain isolated from Citrus limon, under submerged and solid-state fermentation (SmF & SSF, respectively), in the presence and absence of salt (1 M NaCl). The comparative QTOF-LC/MS-based exoproteome analysis of the culture extracts unveiled differential expression of CAZymes, with the higher abundance of GH6 and GH7 family cellobiohydrolase in the presence of 1 M salt. The strain improvement program, employing cyclic mutagenesis and diploidization, was utilized to develop hyper-cellulase producing mutant strains of P. oxalicum. The enzyme production of the developed strain (POx-M35) was further enhanced through statistical optimization of the culture conditions utilizing glucose mix disaccharides (GMDs) as an inducer. This optimization process resulted in the lignocellulolytic cocktail that contained high titers (U/mL) of endoglucanase (EG) (146.16), cellobiohydrolase (CBHI) (6.99), β-glucosidase (β-G) (26.21), xylanase (336.05) and FPase (2.02 U/mL), which were 5.47-, 5.54-, 8.55-, 4.96-, and 4.39-fold higher when compared to the enzyme titers obtained in wild HP1, respectively. Furthermore, the lignocellulolytic cocktails designed by blending secretome produced by mutant POx-M35 with xylanases (GH10 and GH11) derived from Malbranchea cinnamomea resulted in efficient hydrolysis of unwashed acid pretreated (UWAP) rice straw slurry and mild alkali deacetylated (MAD) rice straw. This study underscores the potential of bioprospecting novel fungus and developing an improved strain for optimized production and constitution of lignocellulolytic cocktails that can be an important determinant in advancing biomass conversion technologies.

This study investigates the production of biomethane, and variation in microbial community and coal molecular structures using gas chromatography, 16S rRNA high-throughput sequencing and Fourier transform infrared spectroscopy. Additionally, the factors influencing microbial community structure at a molecular level are discussed. The results demonstrate that bituminous coal exhibits a higher biomethane yield than anthracite coal. In bituminous coal samples, Escherichia and Proteiniphilum are the predominant bacteria at day 0, while Macellibacteroides dominates from days 5 to 35. Methanofollis is the dominated archaea during days 0 to 15, followed by Methanosarcina on day 35. In anthracite coal samples, Soehngenia is the dominant bacterial genus at day 0; however, it transitions to mainly Soehngenia and Aminobacterium within days 5-15 before evolving into Acetomicrobium on day 35. Methanocorpusculum is predominantly found in archaeal communities during days 0-15 but shifts to Methanosarcina on day 35. Alpha diversity analysis reveals that bacterial communities have higher species abundance and diversity compared to archaeal communities. Redundancy analysis indicates a significant correlation between coal molecular structure and bacterial community composition (P value < 0.05), whereas no correlation exists with archaeal community composition (P value > 0.05). The research findings provide theoretical support for revealing the biological gasification mechanisms of coal.

D-glucaric acid is a platform chemical of great importance and the consolidated bioprocessing (CBP) of lignocellulose by the microbial consortium of Trichoderma reesei C10 and Saccharomyces cerevisiae LGA-1C3S2 features prospects in biomanufacturing it. Here we compared some representative lignocelluloses in Northwest China including corn stover, wheat straw and switchgrass, and the leading pretreatments including steam explosion, subcritical water pretreatment, sodium hydroxide pretreatment, aqueous ammonia pretreatment, lime pretreatment, and diluted sulfuric acid pretreatment. It was found that sodium hydroxide pretreated switchgrass (SHPSG) was the best substrate for D-glucaric acid production, resulting in the highest D-glucaric acid titers, 11.69 ± 0.73 g/L in shake flask and 15.71 ± 0.80 g/L in 10L airlift fermenter, respectively. To the best of our knowledge, this is the highest D-glucaric acid production titer from lignocellulosic biomass. This work offers a paradigm of producing low-cost D-glucaric acid for low-carbon polyethylene 2,5-furandicarboxylate (PEF) and a reference on developing biorefinery in Northwest China.

ε-Poly-L-lysine (ε-PL) is a natural and wide-spectrum antimicrobial additive. In this study, the production of ε-PL by Streptomyces albulus FQF-24 using cassava starch (CS) as carbon source and the effects of different feeding methods were investigated in a fermenter. The initial shake flask experiments demonstrated the efficient production of ε-PL with CS, achieving the ε-PL production of 1.18 g/L. Subsequent investigations in the fermenter identified that the ideal pH was 3.8 during the ε-PL synthesis phase. Under this condition, the production of ε-PL reached 1.35 g/L. When the pH was maintained at 3.8, the investigation of improvement of feeding composition was carried out in a 5 L fermenter. The intermittent feeding containing CS, inorganic and organic nitrogen sources resulted in the maximum ε-PL production and dry cell weight (DCW) reaching 17.17 g/L and 42.73 g/L. Additionally, continuous feeding with the composition of CS, organic and inorganic nitrogen sources, and inorganic salts further increased ε-PL production and DCW to 27.56 g/L and 38.5 g/L. Summarily, the above results indicate that the fermentation using low-cost CS and continuous feeding strategy with whole medium composition can provide a beneficial reference for the efficient production of ε-PL.

Droplet-based bioprinting (DBB) allows for high precision, noncontact, and on-demand distribution of bioinks, hence it has been widely utilized in the preparation of bacteria-laden living materials (BLMs). Nonetheless, discontinuous ink deposition makes it challenging to fabricate large-sized intact living structures via this technique. Herein, we explore the way of using DBB to construct centimeter-scale BLMs with bespoke geometries, and further demonstrate its potential applicability in sensing-responsive device by integrating engineered bacteria. We first established a DBB method based on printing-path design, which does not require hardware modification. This strategy was able to produce customized 3D-hydrogel structures with high shape fidelity. Then, we confirmed the excellent biocompatibility of the above biofabrication approach. The Escherichia coli survived 93% ± 4.0% in printed BLMs, with uniform distribution throughout the structure. As a proof-of-concept, we finally manufactured a test strip-like heavy metal biosensor capable of plug-and-play detecting mercury (II) in water using the aforesaid approach. To our knowledge, this is the first study to employ 3D bioprinted BLMs for the detection of prevalent heavy metal pollutants. Our research shed light on the versatility of DBB in BLMs construction, which is not restricted to two-dimensional patterns. Moreover, our results are expected to innovate heavy metal biodetection and improve detection efficiency and sensitivity.

D-pantothenate, universally acknowledged as vitamin B5, has garnered considerable interest owing to its crucial functionality in the feed, pharmaceutical, and cosmeceutical sectors. Development of microbial strains for D-pantothenate hyperproducer has emerged as a prominent research direction in recent years. Herein, we converted an engineered Escherichia coli with low yield to a plasmid-free hyperproducer of D-pantothenate using multiplex combinatorial strategies. First, an initial strain was obtained through prolonging the cell lifespan. To promote the accumulation of D-pantothenic acid, the supply of cofactors was adaptively enhanced. Additionally, the heterologous gene panE from Pseudomonas aeruginosa, which encodes ketopantoate reductase (EC 1.1.1.169) catalyzing the synthesis of d-pantoate from α-ketopantoate, was screened and integrated into the chromosome. Subsequently, a strategy of acetate recycling and NOG pathway reconstruction were introduced and successfully to improve the D-pantothenate titer to 5.48 g/L. Additionally, we screened the regulatory factors and optimized its second codon to further increase the DPA yield of the engineered strains to 6.02 g/L in shake flask. The final engineered strain DS6 could efficiently produce 72.40 g/L D-pantothenate, which is 3.18-fold higher than the original strain. This study proposed a novel multiplex combination strategy for developing microbial cell factory of D-pantothenate, which was beneficial for the advancement of efficient D-pantothenate production.