Biology subjects

Ow, D. S.-W.

Publications and source records attributed to Ow, D. S.-W..

5 recordsLinked to original sources

bioRxiv2025

An Experimental and Multiphysics Simulations Study of Clostridium carboxidivorans sp. 624 for Acid and Alcohol Production in CO2/H2

Biotechnological advances in CO2 utilization through gas fermentation offer a sustainable alternative to energy-intensive chemical processes. This study investigates and optimizes fermentation dynamics of Clostridium carboxidivorans sp. 624 for enhanced production of C2-C6 acids via combined experimental and computational methods. A systematic experimental evaluation of temperature and medium conditions, along with time-course analysis elucidates metabolic pathway regulation. Experimental optimisation, complemented by modelling, identified gas-liquid volumetric ratios VL/VG = 4 as optimal for maximizing longer-chain acids production, attributed to enhanced gas solubility and substrate bioavailability. Additionally, a hybrid model combining dynamic-kinetic model and computational fluid dynamics (CFD) successfully predict product formation. By capturing spatial inhomogeneities in gas-liquid interactions, the model also provides critical insights for optimizing fermentation performance and establishes a framework for improving process design parameters for CO2/H2 fermentation, paving the way for scalable and efficient CO2-based bioprocesses.

microbiology↗

bioRxiv2024

Valorisation of spent cultivated meat media for recombinant FGF2 production in GRAS Lactococcus lactis

Innovative strategies for sustainable utilization of waste resources are imperative in the pursuit of a circular economy. Recently, the idea of utilizing mammalian spent media as a valuable resource is gaining traction, offering significant opportunities for innovative uses as a food-grade feedstock for microbial fermentation, especially in the production of alternative proteins for research and food purposes. In this study, we aim to repurpose spent mammalian culture media for production of valuable proteins. Growth factors (GFs) are a family of high-value proteins that naturally stimulate cell proliferation or differentiation. More importantly, these factors also present significant costs for cell culture. Here, we successfully demonstrate the use of spent mammalian culture media for the recombinant production of fibroblast growth factor 2 (FGF2-G3) in Lactococcus lactis. Bioreactor fermentation at a 1 L scale confirmed purified yields of 2.6 mg/L of recombinant FGF2-G3 using spent media. Further functional testing indicated that the recombinant FGF2-G3 can promote cell proliferation on an Anguilla japonica (Japanese eel) pre-adipocytic cell line, suggesting its potential for cultivated meat production. Based on the preliminary results of this study, our calculations indicate that fermenting 1 L spent mammalian waste could yield enough growth factors to efficiently grow approximately 52 L of cultivated meat through fermentation. This prediction emphasizes the potential of waste valorisation to sustainably produce protein, thus contributing to environmental preservation and economic viability. HighlightsO_LISpent mammalian culture media can be repurposed for microbial fermentation. C_LIO_LIGRAS L. lactis was used to express FGF2-G3 in an optimized spent media formulation. C_LIO_LIFunctional FGF2-G3 expression was demonstrated in controlled 1-L bioreactor runs. C_LI

microbiology↗

bioRxiv2023

Sweetwater: an underrated crude glycerol for sustainable lipid production in non-conventional yeasts

Sweetwater, a methanol-free by-product of the fat splitting process, is an emerging alternative feedstock for microbial utilization of crude glycerol. Yeasts are promising candidates in this context due to their versatility in delivering a wide range of value-added products including lipids. To enhance sweetwater utilization, we investigated the growth and lipid production of 21 oleaginous yeast strains in sweetwater and found that nutrient limitation and the unique carbon composition of sweetwater boosted significant lipid accumulation in several strains, in particular Rhodosporidium toruloides NRRL Y-6987. To decipher the underlying mechanism, the transcriptomic changes of R. toluroides NRRL Y-6987 were further analyzed, indicating potential sugars and oligopeptides in sweetwater supporting growth and lipid accumulation as well as exogenous fatty acid uptake leading to the enhanced lipid accumulation. Our comparative study successfully demonstrated sweetwater as a cost-effective feedstock and suggested potential sweetwater type and strain engineering targets for increasing microbial lipid production. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=139 SRC="FIGDIR/small/558176v1_ufig1.gif" ALT="Figure 1"> View larger version (42K): org.highwire.dtl.DTLVardef@1ad5738org.highwire.dtl.DTLVardef@139227eorg.highwire.dtl.DTLVardef@7a8e1org.highwire.dtl.DTLVardef@e072c6_HPS_FORMAT_FIGEXP M_FIG C_FIG

systems biology↗

bioRxiv2023

A Sweeter Future: Using protein language models for exploring sweeter brazzein homologs

Reducing sugar intake lowers the risk of obesity and associated metabolic disorders. Currently, this is achieved using artificial non-nutritive sweeteners, where their safety is widely debated and their contributions in various diseases is controversial. Emerging research suggests that these sweeteners may even increase the risk of cancer and cardiovascular problems, and some people experience gastrointestinal issues as a result of using them. A safer alternative to artificial sweeteners could be sweet-tasting proteins, such as brazzein, which do not appear to have any adverse health effects. In this study, protein language models were explored as a new method for protein design of brazzein. This innovative approach resulted in the identification of unexpected mutations, which opened up new possibilities for engineering thermostable and potentially sweeter versions of brazzein. To facilitate the characterization of the brazzein mutants, a simplified procedure was developed for expressing and analyzing related proteins. This process involved an efficient purification method using Lactococcus lactis (L. lactis), a generally recognized as safe (GRAS) bacterium, as well as taste receptor assays to evaluate sweetness. The study successfully demonstrated the potential of computational design in producing a more heat-resistant and potentially more palatable brazzein variant, V23.

synthetic biology↗

bioRxiv2021

Systematic evaluation of genome-wide metabolic landscapes in lactic acid bacteria reveals diet-induced and strain-specific probiotic idiosyncrasies

Lactic acid bacteria (LAB) naturally occur in animal and plant niches and are well-known to elicit several health benefits in humans. Yet, how they adapt their functional metabolic landscapes to diverse nutrient environments and synthesize relevant bioactive compounds remain unexplored across genera, species and strains. Hence, presented herein is a systematic framework for comprehensively characterizing the genome-wide metabolisms of six representative LAB by combining multi-omics data with in silico modeling. We analyse the differences in their growth and cellular fitness, biosynthetic capability of health-relevant compounds, i.e., postbiotics, and probable interactions with 15 common gut microbiota under 11 virtual dietary regimes, and show such attributes are diet- and species-specific. Particularly, some LAB exhibit a desirable balance between synthesis of beneficial postbiotic compounds, positive interactions with beneficial gut commensals, and the ability to colonize and persist in gut environment. We also observe that "high fat-low carb" diets likely lead to detrimental outcomes in most LAB. Our results clearly highlight that probiotics are not "one size fits all" commodities and need to be formulated in a personalised manner for their use as dietary supplements and live biotherapeutics. Overall, the proposed framework will systematize the probiotic administration and could also widen the strain repertoire.

systems biology↗