Fachbereich Chemie und Biotechnologie
Refine
Year of publication
Institute
- Fachbereich Chemie und Biotechnologie (931)
- INB - Institut für Nano- und Biotechnologien (86)
- Fachbereich Medizintechnik und Technomathematik (41)
- IAP - Institut fuer Angewandte Polymerchemie (37)
- Nowum-Energy (12)
- IfB - Institut für Bioengineering (10)
- Fachbereich Energietechnik (9)
- Fachbereich Bauingenieurwesen (3)
- Fachbereich Maschinenbau und Mechatronik (3)
- Fachbereich Elektrotechnik und Informationstechnik (2)
Language
- English (565)
- German (363)
- Multiple languages (2)
- Spanish (1)
Document Type
- Article (613)
- Patent (120)
- Book (66)
- Conference: Meeting Abstract (56)
- Conference Proceeding (35)
- Part of a Book (21)
- Report (6)
- Doctoral Thesis (4)
- Bachelor Thesis (3)
- Conference Poster (3)
Keywords
- Heparin (3)
- renewable resources (3)
- Bacillaceae (2)
- Biorefinery (2)
- Biotechnological application (2)
- Butanol (2)
- Chemometrics (2)
- Dietary supplements (2)
- Glucosamine (2)
- IR (2)
The increasing demand for bio-based chemicals and sustainable materials has placed biomass-derived lactic acid in the spotlight as a key building block for biodegradable polylactic acid (PLA). Perennial ryegrass (Lolium perenne) is a promising feedstock due to its high dry matter (DM) yield, adaptability, and widespread agricultural use. This study investigates an integrated lactic acid–silage cascade process, focusing on how pH regulation, harvest timing, and biomass characteristics influence lactic acid production while maintaining agronomic efficiency. The results highlighted the crucial role of pH management and silage duration in optimizing lactic acid production. A silage period of 21 days was found to be optimal, as peak lactic acid yields were consistently observed at this stage. Maintaining a pH range of 4.5 to 6 proved essential for stabilizing fermentation, with citrate buffering at pH 6 leading to the highest lactic acid yields and minimizing undesirable by-products. Harvest timing also significantly affected lactic acid yield per hectare. While later harvesting increased total DM yield, it led to a decline in lactic acid concentration per kg DM. Tetraploid ryegrass (Explosion) maintained stable lactic acid yields due to higher biomass accumulation, whereas diploid varieties (Honroso) experienced a net reduction. From an agronomic perspective, optimizing harvest timing and variety selection is key to balancing biomass yield and fermentation efficiency. While tetraploid varieties offer greater flexibility, diploid varieties require precise harvest timing to avoid losses. These findings contribute to sustainable forage management, improving lactic acid production, silage efficiency, and agricultural resource use.
The industrial production of citric acid, an ingredient in beverages, pharmaceuticals, and cosmetics, is based on microbial fermentation of glucose or sucrose. Given the elevated cost of these sugars, lignocellulosic biomass is emerging as a cost-effective and environmentally friendly feedstock for sustainable bioprocesses. However, fermentation of lignocellulosic materials requires that they are first broken down enzymatically. This can be achieved by the filamentous fungus Aspergillus niger, which has the ability to secrete hydrolytic enzymes and to produce citric acid. Here, we investigated the production of citric acid using a consolidated bioprocess, in which all conversion steps – from the solid substrate to the final product – occurred in a single process stage. The press cake derived from a perennial ryegrass (Lolium perenne) was used as substrate and glucose or the remaining press juice were utilized as an additional carbon source. Aspergillus niger produced citrate successfully only when the press cake was supplemented with press juice (2.1 ± 0.0 g kgDM−1) and especially glucose (84.7 ± 0.3 g kgDM−1). Confocal laser scanning microscopy revealed differences in fungal mycelia based on the carbon source supplemented. Overall, the results indicate the successful implementation of solid-state fermentation for the sustainable production of citric acid by A. niger fed on press cake.
The growing demand for robust proteases in industrial applications, particularly those based on the widely used subtilisin family, necessitates the development of novel and improved enzymes. This study reports exploration and characterization of a subtilisin, AprMH1, isolated from a recently identified Bacillus zhangzhouensis MH1 (NCBI Acct. No. MZ569437). The isolated aprMH1 gene, consisting of 1146 bp and encoding a 381 amino acid protein, was successfully cloned and overexpressed in Bacillus subtilis DB104. The recombinant AprMH1 protease, belonging to the S8 subtilase family and sharing 99.27 % similarity with keratinase Ker1 (ANQ68333.1) of B. pumilus CCUG 66887, displayed remarkable biochemical properties that offer significant industrial potential. It was produced in a one-liter fermenter, yielding 400,000 U after 48 h, and purified to homogeneity by ion-exchange chromatography with a 3.4-fold purification. AprMH1, a monomer of 27.8 kDa, exhibited optimum activity at pH 10 and 55 °C. It remained stable between pH 7–11 and retained 64 % of activity at 50 °C for 1 h. It also remained stable with non-ionic surfactants and its stability with SDS was enhanced by propylene glycol.
Structural insights were gained through 3D modeling and comparative analysis with subtilisin Carlsberg (P00780.2), Apr1 (P07518.1), and Savinase (P29600.1). AprMH1 was found to belong to a distinct alkaline subgroup within the true subtilisin subfamily, exhibiting superior activity and stability at higher temperatures, making it a promising candidate for applications in harsh industrial environments. These novel properties highlight the potential of AprMH1 for future industrial processes, especially in the detergent sector.
Chiral, vicinal diols are of high interest for academic research and industrial applications. For synthesizing chiral diols, enzymes are important catalysts due to their high selectivity and ability to work under tolerable temperature and no pressure. In this study, two consecutive enzyme-catalyzed steps were used for the asymmetric synthesis of aliphatic, vicinal diols with high product concentrations and chiral purity. The reaction comprised a ligation step employing lyases and a subsequent reduction step using oxidoreductases. Either in an aqueous buffer or an organic solvent, the potentially biobased aldehydes acetaldehyde, propanal, butanal, and pentanal were used as substrates. Here, all possible stereoisomers of 2,3-butanediol, 3,4-hexanediol, 4,5-octanediol, and 5,6-decanediol were produced with isomeric content values between 72% and > 99%, and concentrations and conversions between 4.1 and 60 mM. This work shows how four symmetric, chiral, vicinal diols can be synthesized by combining enzymes in a modular way, including exemplarily scaling.
The present invention relates to an isolated polypeptide having aminoacylase activity and comprising an amino acid sequence having over its entire length at least 87 % sequence identity to the amino acid sequence set forth in SEQ ID NO: 1. The invention further relates to an isolated nucleic acid molecule comprising a nucleotide sequence encoding such an aminoacylase, to a plasmid vector comprising said nucleic acid molecule, to a recombinant host cell comprising the isolated nucleic acid molecule or the vector and to methods to produce said aminoacylase. The invention also covers the use of the aminoacylase according to the invention for the N-acylation of amino acids or salts thereof as well as methods to produce N-acyl amino acids or salts thereof using the aminoacylase. Furthermore, the invention relates to the obtained N-acyl amino acids, compositions comprising them and the use of the produced N-acyl amino acids in a cosmetic product, home care product or an industrial and/or institutional product.
In most municipal wastewater treatment plants (MWWTPs) that employ activated sludge systems for nitrogen (N) removal, aeration accounts for approximately 50–60 % of all electricity consumption. Deammonifikation (DEA) is well-recognized as an energy–efficient technology although its mainstream implementation is still questionable. The aim of the presented work was to determine the operational window of various deammonifying sludges (S1–S7) in NRW from side of MWWTPs with respect to the operational factors temperature (8–50 °C), pHvalue (3.5–10.5), and COD/N ratio (0.5–6). Efficiencies up to 3 mg N L⁻¹h⁻¹were achievable even below 15 °C except for S6. All of the sludges except S6 achieved an elimination rate of more than 2.08–16 mg N L⁻¹ h⁻¹ in the main stream pH range (7–8). At a COD/N ratio > 1.5, the metabolism of DEA was disturbed. Although N/DN was suspected to have occurred at higher COD/N ratio, no increase in elimination rate was observed for most of the sludges. All the sludges fulfilled the minimum requirement of N-elimination rate (2.08 mg N L⁻¹h⁻¹ ), which leads to a comparable reactor volume to conventional WWTP. A large-scale implementation of a main stream DEA in full stream cannot yet be recommended on the basis of these results but semi-technical trials.
Bioelectrochemical systems (BESs) offer a sustainable method for chemical production, including the enhanced production of succinic acid. By combining fermentation with BES, it could be possible to achieve sustainable succinic acid production and CO2 fixation using Actinobacillus succinogenes. In literature, the potential application of BES is commonly associated with increased succinate yields, as it is expected to enhance the availability of NADH, thereby influencing the intracellular nicotinamide adenine dinucleotide (NADH/NAD+) balance. However, it remains unclear whether BES can improve NADH regeneration and achieve higher NADH/NAD+ ratios across all growth phases of A. succinogenes. This study investigates the impact of an applied electrical potential on the intracellular NADH/NAD+ ratio during an electrochemical-assisted fermentation process. Using an adapted high-performance liquid chromatography method with a Supelcosil LC-18-T column, it was demonstrated that NADH availability in BES, particularly during the stationary growth phase, improved by up to 1.98-fold compared to the control. This enhancement in reducing power led to a succinate yield of 0.747 ± 0.01 g g−1, representing a 15.65% increase compared to a fermentation without electrochemical assistance. These findings support the expectation that the use of BES could enhance the competitiveness of bio-based succinate production.
Industrial digestates from short-fibre residues, generated in paper recycling mills, are driving interest in resource recovery. This study aims to explore their potential for water recovery. Understanding particle dynamics aids in optimizing dewatering for digestate management. The particle size distribution in this study revealed significant fractions: <0.63 μm (6–20%), 0.63–20 μm (38–52%), and >20 μm (11–16%). Pre-treatment with Na4P2O7 and H2O2 enhances settling and lowers total dissolved solids (TDSs) but results in variation of size distribution. Additionally, this study investigates further water reuse in paper mills, focusing on the quality of ultrafiltration (UF) permeate obtained from the digestate of short fibres. UF permeate analysis reveals deviations from freshwater standards in paper mills. Despite effective TS removal, UF permeate falls short of paper mill water standards due to high TDSs, electrical conductivity, and nutrient concentrations, necessitating further downstream treatment with nanofiltration or reverse osmosis. A substantial reduction of permeate flux from 31 to 5 L/(m2·h) over the time indicated fouling and inefficient membrane wash. The silt density index of the UF membrane at 30 min registered 2.1, suggesting potential fouling. Further investigations on optimizing UF operations to enhance permeate flux and exploring alternative UF membranes are required.
There is a lack of fast and inexpensive analytical methods for quantification of key ingredients in dietary supplements. Here we explore the potential of near infrared (NIR) spectrometry, attenuated total reflection infrared (ATR-IR) spectrometry and potentiometric multisensor system (MSS) in quantitative determination of glucosamine and hyaluronic acid in commercial samples of dietary supplements. All three methods have demonstrated their applicability for this task when combined with chemometric data processing. Principal Component Analysis (PCA) revealed similarities across the three techniques, indicating the presence of distinct sample compositions. Partial least squares (PLS) models were constructed for glucosamine and hyaluronic acid quantification. The root mean square error of cross validation (RMSECV) for glucosamine quantification varied between 7.7 wt% and 8.9 wt%. NIR spectrometry has demonstrated the best accuracy for hyaluronic acid (RMSECV = 9.9 wt%), while ATR-IR and MSS yielded somewhat worse performance with RMSECV values of 12.1 and 11.3 wt%, respectively. The findings of this study indicated that NIR, ATR-IR and MSS exhibit reduced accuracy in comparison to complex and high-precision analytical techniques. However, they can be employed for the rapid, semi-quantitative evaluation of glucosamine and hyaluronic acid in dietary supplements, with the possibility of integration into routine quality control procedures.