Application of response surface methodology for the optimization of arabinose biotransformation to arabitol by Candida parapsilosis

The Industrial Application Potential of Sugar Beet Pulp Derived Monosaccharides d-Galacturonic Acid and l-Arabinose

This review provides a perspective on the industrial application potential of sugar beet pulp (SBP) derived monosaccharides. The broad application of these monosaccharides could contribute to bio-based alternatives and sustainable practices, essential for the transition towards a more circular economy. This review focuses on the utilization and application of two SBP monosaccharides, d-galacturonic acid (d-GalA) and l-arabinose (l-Ara), derived from pectin and hemicellulose. These polysaccharides are major components of sugar beet pulp, an important side stream of sucrose production. d-GalA and l-Ara are therefore abundant in biomass and offer unique molecular structures amenable to selective chemical or enzymatic modifications. We review their application in various industrial applications such as the development and production of bioactive compounds, home and personal care products, and other industries.

Optimization of biotransformation processes of Camarosporium laburnicola to improve production yields of potent telomerase activators

BACKGROUND

Telomerase activators are promising agents for the healthy aging process and the treatment/prevention of short telomere-related and age-related diseases. The discovery of new telomerase activators and later optimizing their activities through chemical and biological transformations are crucial for the pharmaceutical sector. In our previous studies, several potent telomerase activators were discovered via fungal biotransformation, which in turn necessitated optimization of their production. It is practical to improve the production processes by implementing the design of experiment (DoE) strategy, leading to increased yield and productivity. In this study, we focused on optimizing biotransformation conditions utilizing Camarosporium laburnicola, a recently discovered filamentous fungus, to afford the target telomerase activators (E-CG-01, E-AG-01, and E-AG-02).

RESULTS

DoE approaches were used to optimize the microbial biotransformation processes of C. laburnicola. Nine parameters were screened by Plackett-Burman Design, and three significant parameters (biotransformation time, temperature, shaking speed) were optimized using Central Composite Design. After conducting validation experiments, we were able to further enhance the production yield of target metabolites through scale-up studies in shake flasks (55.3-fold for E-AG-01, 13-fold for E-AG-02, and 1.96-fold for E-CG-01).

CONCLUSION

Following a process optimization study using C. laburnicola, a significant increase was achieved in the production yields. Thus, the present study demonstrates a promising methodology to increase the production yield of potent telomerase activators. Furthermore, C. laburnicola is identified as a potential biocatalyst for further industrial utilization.

Improvement of caffeic acid biotransformation into para-hydroxybenzoic acid by Candida albicans CI-24 via gamma irradiation and model-based optimization

Para-hydroxybenzoic acid (PHBA) has great potential in biological applications due to its putative antiviral activity against SARS-CoV-2 and its antimicrobial activity in the face of the radically increasing number of multidrug-resistant pathogens. This is in addition to its antimutagenic, anti-inflammatory, antioxidant, hypoglycemic, antiestrogenic, and antiplatelet aggregating activities. In this study, an approximate sixfold increase in the production of PHBA was achieved via biotransformation of caffeic acid by Candida albicans. The improvement was performed in two steps: first, through mutation by gamma irradiation (5 KGy dose), resulting in the recovery of a mutant (CI-24), which produced approximately triple the amount of PHBA produced by the wild-type isolate. Then, biotransformation by this mutant was further optimized via response surface methodology model-based optimization. The maximum PHBA production (7.47 mg/mL) was obtained in a fermentation medium composed of 1% w/v yeast extract as a nitrogen source, with an initial pH of 6.6, incubated at 28 °C at an agitation rate of 250 rpm. To further enhance the performance and economics of the process, cells of the CI-24 mutant were immobilized in calcium alginate beads and could retain an equivalent biotransformation capacity after three successive biotransformation cycles.

Valorization of Crude Glycerol, Residue Deriving from Biodiesel- Production Process, with the Use of Wild-type New Isolated Yarrowia lipolytica Strains: Production of Metabolites with Pharmaceutical and Biotechnological Interest

BACKGROUND & OBJECTIVE

Crude glycerol (Glol), used as substrate for screening eleven natural Yarrowia lipolytica strains in shake-flask experiments. Aim of this study was to assess the ability of the screened strains to produce biomass (dry cell weight; X), lipid (L), citric acid (Cit), mannitol (Man), arabitol (Ara) and erythritol (Ery), compounds presenting pharmaceutical and biotechnological interest, in glycerol-based nitrogen-limited media, in which initial glycerol concentration had been adjusted to 40 g/L.

METHODS

Citric acid may find use in biomedical engineering (i.e. drug delivery, tissue engineering, bioimaging, orthopedics, medical device coating, wound dressings). Polyols are considered as compounds with non-cariogenic and less calorigenic properties as also with low insulin-mediated response. Microbial lipids containing polyunsaturated fatty acids (PUFA) are medically and dietetically important (selective pharmaceutical and anticancer properties, aid fetal brain development, the sight function of the eye, hormonal balance and the cardio-vascular system, prevent reasons leading to type-2 diabetes, present healing and anti-inflammatory effects).

RESULTS

All strains presented satisfactory microbial growth (Xmax=5.34-6.26 g/L) and almost complete substrate uptake. The principal metabolic product was citric acid (Citmax=8.5-31.7 g/L). Production of cellular lipid reached the values of 0.33-0.84 g/L. Polyols were also synthesized as strain dependent compounds (Manmax=2.8-6.1 g/L, Aramax ~2.0 g/L, Erymax= 0.5-3.8 g/L). The selected Y. lipolytica strain ACA-DC 5029 presented satisfactory growth along with synthesis of citric acid and polyols, thus, was further grown on media presenting an increased concentration of Glol~75 g/L. Biomass, lipid and citric acid production presented significant enhancement (Xmax=11.80 g/L, Lmax=1.26 g/L, Citmax=30.8 g/L), but conversion yield of citric acid produced per glycerol consumed was decreased compared to screening trials. Erythritol secretion (Erymax=15.6 g/L) was highly favored, suggesting a shift of yeast metabolism from citric acid accumulation towards erythritol production. Maximum endopolysaccharides (IPS) concentration was 4.04 g/L with yield in dry weight 34.2 % w/w.

CONCLUSION

Y. lipolytica strain ACA-YC 5029 can be considered as a satisfactory candidate grown in high concentrations of crude glycerol to produce added-value compounds that interest pharmaceutical and biotechnology industries.