Structure elucidation of a galactofuranose-rich heteropolysaccharide from aciduric fungus penicillium purpurogenum JS03-21.

The exopolysaccharide-producing fungus Penicillium purpurogenum JS03-21 from the acidic purple clay was screened to develop greater insights into microbial exopolysaccharide resources from extremophilic microorganisms. An exopolysaccharide JS1-1 was purified from the fermented broth of the aciduric fungus using a combination of ethanol precipitation, anion-exchange and size-exclusion chromatography. JS1-1 was found to be a neutral heteropolysaccharide composed of galactose, mannose and glucose in the ratio of 7.9:2.1:1.0, with a molecular weight of about 26 kDa. JS1-1 was subjected to a series of methylation and partial acid hydrolysis reactions, as well as being analyzed by one- and two-dimensional nuclear magnetic resonance, and the results of these analyses revealed JS1-1 to be a galactofuranose-rich polysaccharide. The main chain of JS1-1 contained two regions, including a galactose part composed of a repeating trisaccharide unit [i.e., →5)-ß-D-Galf(1 → 5)-ß-D-Galf(1 → 6)-ß-D-Galf(1→], and a mannose section consisting of (1 → 6)-linked α-D-Manp residues. Two further segments [i.e., α-D-Glcp(1 → 2)-α-D-Galf (1 → and α-D-Galf(1 → 2)-α-D-Manp(1→] existed as branches that were linked to the O-2 atoms of the (1 → 6)-ß-D-Galf and (1 → 6)-α-D-Manp regions of the main chain, respectively. The results of the current study demonstrate that JS1-1 is a unique polysaccharide that is rich in both α and ß galactofuranose units and therefore different from most of the other known extracellular polysaccharides. The function of this polysaccharide is currently being researched in our laboratory.

Advance toward function, production, and delivery of natural astaxanthin: A promising candidate for food ingredients with future perspectives.

Astaxanthin (AST) exhibits potent antioxidant activity, effectively preventing neurological diseases and cancer. Presently, producing AST from microorganisms like Haematococcus pluvialis and Phaffia rhodozyma is a growing trend. This review summarizes the main research topics on AST in the past five years. AST plays a crucial role in cancer and diabetes prevention, as well as neuroprotection, however, the presence of both free and esterified forms of AST results in differences in their functionality and applications. The primary challenges in industrial production of natural AST lie in breeding high-yield natural producers and developing methods to enhance yield. The use of high-quality food matrix materials and preparation methods is crucial for the delivery system of loaded AST. This study elucidates the bottlenecks and future development directions encountered by natural AST during industrialization, aiming to promote the healthy and rapid growth of the food industry.

Purification and partial characterization of an acidic polysaccharide with complement fixing ability from the stems of Avicennia marina.

An acidic polysaccharide fraction that had high anticomplementary activity was isolated from the stems of Grey Mangrove in 0.15% yield. The final fractions was designated HAM-3-IIb-II. The polysaccharide fraction appeared to be homogenous by high performance size exclusion chromatography with an estimated molecular weight of 105 kDa. The isolated polysaccharide is more effective than polysaccharide K (PSK) in its anticomplementary activity at 58 microg/ml of PSK and 23 microg/ml of HAM-3-IIb-II that inhibit 50% of complement activity in the complement fixation assay. Structural studies indicated that HAM-3-IIb-II was rich in galacturonic acid along with arabinose, galactose and rhamnose, characterizing a pectin-type polysaccharide, which was also confirmed by FT-IR spectrum. The presence of rich neutral sugar side chains of arabinogalactans may have contributed to the expression of high activity. Traditionally, this mangrove plant is used for medicinal purposes and it appears to have some scientific applications.