α-D-mannan from Aureobasidium pullulans (CCMB 324): optimization extraction

ARTP mutagenesis of Aureobasidium pullulans RM1603 for high pullulan production and transcriptome analysis of mutants

Pullulan is a microbial exopolysaccharide produced by Aureobasidium spp. with excellent physical and chemical properties, resulting in great application value. In this study, a novel strain RM1603 of Aureobasidium pullulans with high pullulan production of 51.0 ± 1.0 g·L- 1 isolated from rhizosphere soil was subjected to atmospheric and room temperature plasma (ARTP) mutagenesis, followed by selection of mutants to obtain pullulan high-producing strains. Finally, two mutants Mu0816 and Mu1519 were obtained, with polysaccharide productions of 58.7 ± 0.8 and 60.0 ± 0.8 g∙L- 1 after 72-h fermentation, representing 15.1 and 17.6% increases compared with the original strain, respectively. Transcriptome analysis of the two mutants and the original strain revealed that the high expression of α/β-hydrolase (ABHD), α-amylase (AMY1), and sugar porter family MFS transporters (SPF-MFS) in the mutants may be related to the synthesis and secretion of pullulan. These results demonstrated the effectiveness of ARTP mutagenesis in A. pullulans, providing a basis for the investigation of genes related to pullulan synthesis and secretion.

Three new griseofulvin derivatives from Aureobasidium pullulans

Three new griseofulvin derivatives, griseofulvinoside A-C (1-3), were isolated from the ethyl acetate extract of the solid fermentation product of Aureobasidium pullulans. Their structures were elucidated based on extensive spectroscopic data analysis of MS, 1D and 2D NMR. The antifungal activities of new compounds were evaluated against four phytopathogenic fungi in vitro, and all test compounds demonstrated inhibitory effects. Among them, compound 2 exhibited the most potent activities against the four selected phytopathogenic fungi with inhibitory rates ranging from 40.2 to 75.8% at 0.2 mg/mL.

Antinociceptive and anti-inflammatory properties of α-D-mannan from the yeast Kluyveromyces marxianus: evidence for a role in interleukin-6 inhibition

The management of inflammatory states typically involves non-steroidal anti-inflammatory drugs (NSAIDs) and opiates. Understanding the mechanisms underlying the processing of nociceptive information from potential alternatives such as some polysaccharides may enable new and meaningful therapeutic approaches. In this study, α-D-mannan isolated from the Kluyveromyces marxianus cell wall produced antinociceptive effects in models of inflammatory pain (formalin and complete Freund's adjuvant tests). Furthermore, α-D-mannan reduced paw edema and interleukin-6 (IL-6) production after carrageenan-induced inflammation. The polysaccharide α-D-mannan was characterized by gas chromatography-mass spectrometry, methylation analysis, and spectroscopic techniques. Moreover, the Doehlert experimental design was applied to find the optimal conditions for biomass production, with the best conditions being 10.8 g/L and 117 h for the glucose concentration and the fermentation time, respectively. These results indicate that α-D-mannan from K. marxianus exerts anti-inflammatory and antinociceptive effects in mice, possibly via a mechanism dependent on the inhibition of IL-6 production.

Biological Activities of Citrus aurantium Leaf Extract by Optimized Ultrasound-Assisted Extraction

Several studies have explored the biological activities of Citrus aurantium flowers, fruits, and seeds, but the bioactivity of C. aurantium leaves, which are treated as waste, remains unclear. Thus, this study developed a pilot-scale ultrasonic-assisted extraction process using the Box-Behnken design (BBD) for the optimized extraction of active compounds from C. aurantium leaves, and their antityrosinase, antioxidant, antiaging, and antimicrobial activities were evaluated. Under optimal conditions in a 150× scaleup configuration (a 30 L ultrasonic machine) of a pilot plant, the total phenolic content was 69.09 mg gallic acid equivalent/g dry weight, which was slightly lower (3.17%) than the theoretical value. The half maximal inhibitory concentration of C. aurantium leaf extract (CALE) for 2,2-diphenyl-1-picrylhydrazyl-scavenging, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)-scavenging, antityrosinase, anticollagenase, antielastase and anti-matrix metalloprotein-1 activities were 123.5, 58.5, 181.3, 196.4, 216.3, and 326.4 mg/L, respectively. Moreover, the minimal inhibitory concentrations for bacteria and fungi were 150-350 and 500 mg/L, respectively. In total, 17 active compounds were detected in CALE-with linalool, linalyl acetate, limonene, and α-terpineol having the highest concentrations. Finally, the overall transdermal absorption and permeation efficiency of CALE was 95.9%. In conclusion, our CALE demonstrated potential whitening, antioxidant, antiaging, and antimicrobial activities; it was also nontoxic and easily absorbed into the skin as well as inexpensive to produce. Therefore, it has potential applications in various industries.