Riboflavin is a crucial micronutrient that is a precursor to coenzymes flavin mononucleotide and flavin adenine dinucleotide, and it is required for biochemical reactions in all living cells. For decades, one of the most important applications of riboflavin has been its global use as an animal and human nutritional supplement. Being well-informed of the latest research on riboflavin production via the fermentation process is necessary for the development of new and improved microbial strains using biotechnology and metabolic engineering techniques to increase vitamin B2 yield. In this review, we describe well-known industrial microbial producers, namely, Ashbya gossypii , Bacillus subtilis , and Candida spp. and summarize their biosynthetic pathway optimizations through genetic and metabolic engineering, combined with random chemical mutagenesis and rational medium components to increase riboflavin production.

The psychrophilic marine bacterium, Cobetia marina, recovered from the mantle tissue of the marine mussel, Crenomytilus grayanus, which contained a gene encoding alkaline phosphatase (AP) with apparent biotechnology advantages. The enzyme was found to be more efficient than its counterparts and showed k cat value 10-to 100-fold higher than those of all known commercial APs. The enzyme did not require the presence of exogenous divalent cations and dimeric state of its molecule for activity. The recombinant enzyme (CmAP) production and purification were optimized with a final recovery of 2 mg of the homogenous protein from 1 L of the transgenic Escherichia coli Rosetta(DE3)/Pho40 cells culture. CmAP displayed a half-life of 16 min at 45°C and 27 min at 40°C in the presence of 2 mM EDTA, thus suggesting its relative thermostability in comparison with the known cold-adapted analogues. A high concentration of EDTA in the incubation mixture did not appreciably inhibit CmAP. The enzyme was stable in a wide range of pH (6.0-11.0). CmAP exhibited its highest activity at the reaction temperature of 40-50°C and pH 9.5-10.3. The structural features of CmAP could be the reason for the increase in its stability and catalytic turnover. We have modeled the CmAP 3D structure on the base of the high-quality experimental structure of the close homologue Vibrio sp. AP (VAP) and mutated essential residues predicted to break Mg 2+ bonds in CmAP. It seems probable that the intrinsically tight binding of catalytic and structural metal ions together with the flexibility of intermolecular and intramolecular links in CmAP could be attributed to the adapted mutualistic lifestyle in oceanic waters.

An alkaline phosphatase with unusually high specific activity has been found to be produced by the marine bacterium Cobetia marina (strain KMM MC-296) isolated from coelomic liquid of the mussel Crenomytilus grayanus. The properties of enzyme, such as a very high specific activity (15000 DE U/1 mg of protein), no activation with divalent cations, resistance to high concentrations of inorganic phosphorus, as well as substrate specificity toward 5' nucleotides suggest that the enzyme falls in an intermediate position between unspecific alkaline phosphatases (EC 3.1.3.1) and 5' nucleotidases (EC 3.1.3.5).

Filamentous fungi possess the metabolic capacity to degrade environment organic matter, much of which is the plant and algae material enriched with the cell wall carbohydrates and polyphenol complexes that frequently can be assimilated by only marine fungi. As the most renewable energy feedstock on the Earth, the plant or algae polymeric substrates induce an expression of microbial extracellular enzymes that catalyze their cleaving up to the component sugars. However, the question of what the marine fungi contributes to the plant and algae material biotransformation processes has yet to be highlighted sufficiently. In this review, we summarized the potential of marine fungi alternatively to terrestrial fungi to produce the biotechnologically valuable extracellular enzymes in response to the plant and macroalgae polymeric substrates as sources of carbon for their bioconversion used for industries and bioremediation.

OH-PBDEs and OH-PBDDs from Dysideidae sponges at micro molar levels irreversibly inhibit the bacterial α-galactosidase of the GH36 family.

Many microbial producers of coenzyme B12 family cofactors together with their metabolically interdependent pathways are comprehensively studied and successfully used both in natural ecosystems dominated by auxotrophs, including bacteria and mammals, and in the safe industrial production of vitamin B12. Metabolic reconstruction for genomic and metagenomic data and functional genomics continue to mine the microbial and genetic resources for biosynthesis of the vital vitamin B12. Availability of metabolic engineering techniques and usage of affordable and renewable sources allowed improving bioprocess of vitamins, providing a positive impact on both economics and environment. The commercial production of vitamin B12 is mainly achieved through the use of the two major industrial strains, Propionobacterium shermanii and Pseudomonas denitrificans, that involves about 30 enzymatic steps in the biosynthesis of cobalamin and completely replaces chemical synthesis. However, there are still unresolved issues in cobalamin biosynthesis that need to be elucidated for future bioprocess improvements. In the present work, we review the current state of development and challenges for cobalamin (vitamin B12) biosynthesis, describing the major and novel prospective strains, and the studies of environmental factors and genetic tools effecting on the fermentation process are reported.

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