A sophorolipid is a surface-active glycolipid compound that can be synthesized by a selected number of non-pathogenic yeast species. [1] They are potential bio-surfactants due to their biodegradability and low eco-toxicity.
Sophorolipids are glycolipids consisting of a hydrophobic fatty acid tail of 16 or 18 carbon atoms and a hydrophilic carbohydrate head sophorose, a glucose-derived di-saccharide with an unusual β-1,2 bond and can be acetylated on the 6′- and/or 6′′- positions. One terminal or sub terminal hydroxylated fatty acid is β-glycosidically linked to the sophorose module. The carboxylic end of this fatty acid is either free (acidic or open form) or internally esterified at the 4′′ or in some rare cases at the 6′- or 6′′-position (lactonic form). [2] The physicochemical and biological properties of sophorolipids are significantly influenced by the distribution of the lactone vs. acidic forms produced in the fermentative broth. In general, lactone sophorolipids are more efficient in reducing surface tension and are better antimicrobial agents, whereas acidic sophorolipids display better foaming properties. Acetyl groups can also lower the hydrophilicity of sophorolipids and enhance their antiviral and cytokine stimulating effects. [3]
Sophorolipids are produced by various non pathogenic yeast species such as Candida apicola, Rhodotorula bogoriensis, [5] Wickerhamiella domercqiae, [6] and Starmerella bombicola. [7] [8] Recent research has meant sophorolipids can be recovered during a fermentation using a gravity separator in a loop with the bioreactor, enabling the production of >770 g/L sophorolipid at a productivity 4.24 g/L/h, some of the highest values seen in a fermentation process [9] Desirable properties of biosurfactants are biodegradability and low toxicity. [10] [11] Sophorolipids produced by several yeasts belonging to candida and the starmerella clade, [12] [13] and Rhamnolipid produced by Pseudomonas aeruginosa [14] etc.
Besides biodegradability, low toxicity, and high production potential, sophorolipids have a high surface and interfacial activity. Sophorolipids are reported to lower surface tension (ST) of water from 72 to 30-35 mN/m and the interfacial tension (IT) water/hexadecane from 40 to 1 mN/m. [15] In addition to this, sophorolipids are reported to function under wide ranges of temperatures, pressures and ionic strengths; and they also possess a number of other useful biological activities including Antimicrobial, [5] virucidal, [3] Anticancer, Immuno-modulatory properties. [5]
A detailed and comprehensive literature review on the various aspects of sophorolipids production (e.g. producing micro-organisms, bio-synthetic pathway, effect of medium components and other fermentation conditions and downstream process of sophorolipids is available in the published work of Van Bogaert et al. [5] [16] This work also discusses potential application of sophorolipids (and their derivatives) as well as the potential for genetic engineering strains to enhance sophorolipid yields. Researchers have focused on optimization of sophorolipid production in submerged fermentation, [17] [18] but some efforts have also investigated the possibility of sophorololipid production using solid state fermentation (SSF). [4] The production process can be significantly impacted by the specific properties of the carbon and oil substrates used; and several inexpensive alternatives to more traditional substrates have been investigated. These potential substrates include: biodiesel by-product streams, [19] waste frying oil, [20] [21] restaurant waste oil, [22] industrial fatty acid residues, [23] mango seed fat, [24] and soybean dark oil. The use of most of these substrates have resulted in lower yields compared to traditional fermentation substrates.
To enhance the performance of surfactant properties of natural sophorolipids, chemical modification methods have been actively pursued. [25] Recently, researchers demonstrated the possibility of applying sophorolipids as building blocks via ring-opening metathesis polymerization for a new type of polymers, known as polysophorolipids which show promising potentials in biomaterials applications. [26]
Polyhydroxyalkanoates or PHAs are polyesters produced in nature by numerous microorganisms, including through bacterial fermentation of sugars or lipids. When produced by bacteria they serve as both a source of energy and as a carbon store. More than 150 different monomers can be combined within this family to give materials with extremely different properties. These plastics are biodegradable and are used in the production of bioplastics.
Acidogenesis is the second stage in the four stages of anaerobic digestion:
Industrial fermentation is the intentional use of fermentation in manufacturing products useful to humans. In addition to the mass production of fermented foods and drinks, industrial fermentation has widespread applications in chemical industry. Commodity chemicals, such as acetic acid, citric acid, and ethanol are made by fermentation. Moreover, nearly all commercially produced industrial enzymes, such as lipase, invertase and rennet, are made by fermentation with genetically modified microbes. In some cases, production of biomass itself is the objective, as is the case for single-cell proteins, baker's yeast, and starter cultures for lactic acid bacteria used in cheesemaking.
The rumen, also known as a paunch, is the largest stomach compartment in ruminants and the larger part of the reticulorumen, which is the first chamber in the alimentary canal of ruminant animals. The rumen's microbial favoring environment allows it to serve as the primary site for microbial fermentation of ingested feed. The smaller part of the reticulorumen is the reticulum, which is fully continuous with the rumen, but differs from it with regard to the texture of its lining.
An amphiphile, or amphipath, is a chemical compound possessing both hydrophilic and lipophilic (fat-loving) properties. Such a compound is called amphiphilic or amphipathic. Common amphiphilic compound is surfactant, which is a main ingredient of soaps, detergents, and lipoproteins. The phospholipid amphiphiles are the major structural component of cell membranes.
In biology, syntrophy, synthrophy, or cross-feeding is the phenomenon of one species feeding on the metabolic products of another species to cope up with the energy limitations by electron transfer. In this type of biological interaction, metabolite transfer happens between two or more metabolically diverse microbial species that live in close proximity to each other. The growth of one partner depends on the nutrients, growth factors, or substrates provided by the other partner. Thus, syntrophism can be considered as an obligatory interdependency and a mutualistic metabolism between two different bacterial species.
Surfactin is a cyclic lipopeptide, commonly used as an antibiotic for its capacity as a surfactant. It is an amphiphile capable of withstanding hydrophilic and hydrophobic environments. The Gram-positive bacterial species Bacillus subtilis produces surfactin for its antibiotic effects against competitors. Surfactin showcases antibacterial, antiviral, antifungal, and hemolytic effects.
Biosurfactant usually refers to surfactants of microbial origin. Most of the biosurfactants produced by microbes are synthesized extracellularly and many microbes are known to produce biosurfactants in large relative quantities. Some are of commercial interest. As a secondary metabolite of microorganisms, biosurfactants can be processed by the cultivation of biosurfactant producing microorganisms in the stationary phase on many sorts of low-priced substrates like biochar, plant oils, carbohydrates, wastes, etc. High-level production of biosurfactants can be controlled by regulation of environmental factors and growth circumstances.
Long-chain alcohol oxidase is one of two enzyme classes that oxidize long-chain or fatty alcohols to aldehydes. It has been found in certain Candida yeast, where it participates in omega oxidation of fatty acids to produce acyl-CoA for energy or industrial use, as well as in other fungi, plants, and bacteria.
The National Institute of Molecular Biology and Biotechnology, also known as NIMBB, is a research institute of the University of the Philippines (UP). It has four branches distributed across various UP campuses, namely: UP Diliman (NIMBB-Diliman), UP Los Baños (BIOTECH-UPLB), UP Manila and UP Visayas.
Dark fermentation is the fermentative conversion of organic substrate to biohydrogen. It is a complex process manifested by diverse groups of bacteria, involving a series of biochemical reactions using three steps similar to anaerobic conversion. Dark fermentation differs from photofermentation in that it proceeds without the presence of light.
Starmerella is a genus of fungi within the Saccharomycetales order. The relationship of this taxon to other taxa within the order is unknown, and it has not yet been placed with certainty into any family. Although, the GBIF list the family as Phaffomycetaceae. Several members of the Starmerella clade are associated with flowers and flower-visiting insects like bees and bumblebees; these yeasts cope well with high sugar niches. Many strains (species) of the Starmerella clade, including Starmerella bombicola and Candida apicola are known to produce sophorolipids which are carbohydrate-based, amphiphilic biosurfactants.
Single cell oil, also known as Microbial oil consists of the intracellular storage lipids, triacyglycerols. It is similar to vegetable oil, another biologically produced oil. They are produced by oleaginous microorganisms, which is the term for those bacteria, molds, algae and yeast, which can accumulate 20% to 80% lipids of their biomass. The accumulation of lipids take place by the end of logarithmic phase and continues during station phase until carbon source begins to reduce with nutrition limitation.
Rhamnolipids are a class of glycolipid produced by Pseudomonas aeruginosa, amongst other organisms, frequently cited as bacterial surfactants. They have a glycosyl head group, in this case a rhamnose moiety, and a 3-(hydroxyalkanoyloxy)alkanoic acid (HAA) fatty acid tail, such as 3-hydroxydecanoic acid.
Qū, qú, qūniè, jiǔqū, or jiǔmǔ is a type of East Asian dried fermentation starter grown on a solid medium and used in the production of traditional Chinese alcoholic beverages. The Chinese character 曲/麹 is romanised as qū in pinyin, chhu or chu in other transcription systems. The literal translation of jiǔqū is "liquor ferment", although "liquor mold" or "liquor starter" are adequate descriptions.
The role of yeast in winemaking is the most important element that distinguishes wine from fruit juice. In the absence of oxygen, yeast converts the sugars of the fruit into alcohol and carbon dioxide through the process of fermentation. The more sugars in the grapes, the higher the potential alcohol level of the wine if the yeast are allowed to carry out fermentation to dryness. Sometimes winemakers will stop fermentation early in order to leave some residual sugars and sweetness in the wine such as with dessert wines. This can be achieved by dropping fermentation temperatures to the point where the yeast are inactive, sterile filtering the wine to remove the yeast or fortification with brandy or neutral spirits to kill off the yeast cells. If fermentation is unintentionally stopped, such as when the yeasts become exhausted of available nutrients and the wine has not yet reached dryness, this is considered a stuck fermentation.
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Edible oil refining is a set of processes or treatments necessary to turn vegetable raw oil into edible oil.