Biotechnology, molecular biology and genetic engineering, and bioprospecting play a crucial role in our common future, enabling industrially important microorganisms to ensure sustainable products (fuels, chemicals, pharmaceuticals, food, drug delivery systems, medical devices etc.) and new bioeconomic opportunities. Biotechnological applications are able to provide cost-effective green alternatives to conventional industrial processes, which are currently affecting the nature and biodiversity. Klebsiella species are among the well-studied microbes both in medicine field, as ones of the most resilient opportunistic pathogens, and in industry, due to their promising biochemical properties, and their potential as better hosts than other microorganisms, for i.e. in genetic manipulation. Klebsiella oxytoca and Klebsiella pneumoniae are ubiquitously found in natural environments, but also as commensals in the human gut, and associated with a high-resistance to the first-line antibiotics. However, these specific strains are continuously isolated and studied for different industrial purposes (i.e. bulk chemicals and biofuels production, medical diagnosis, nanoparticles and exopolysaccharides synthesis, plant growth promoting activities, bioremediation and biodegradation agents etc.), and scientific results regarding their biotechnological potential could generate big impact for global bioeconomy development. Recently, research in synthetic biology gained a lot of attention, and new techniques highlight ways to reprogramme these microbial cells in view of high-yield or high-quality new chemicals obtainment. Therefore, some scientific research niches are emerging in biotechnology, and unknown metabolic pathways and genes are identified and further studied, to provide alternative solutions to the global challenges.

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Fungal exopolysaccharides (EPSs) represent an important group of bioactive compounds secreted by fungi. These biopolymers can be utilized individually or in combination with different bioactive substances for a broad range of pharmaceutical field applications, due to their various biological activities, such as antioxidant, antimicrobial, anti-inflammatory, antiviral, anti-diabetic, and anticoagulant effects. The paper presents an up-to-date review of the main fungal polysaccharides (pullulan, schizophyllan, scleroglucan, botryosphaeran, lentinan, grifolan, and lasiodiplodan), highlighting their structures, producing strains, and useful properties in a double position, as controlled release (rate and selectively targeting) drug carriers, but mostly as active immunomodulating and antitumor compounds in cancer therapy.

Since they are more environmentally acceptable than their chemically synthesized counterparts, biosurfactants are used in a wide range of environmental applications. However, less research has been done on biosurfactants within the context of the circular economy, despite their theoretical potential to fulfill a number of circular economy ambitions, including closing the consumption loop, regenerating natural systems, and maintaining resource value within the system. Hence, the main objective of this review is to identify and analyze the contributions of biosurfactants to the implementation of the circular economy. A final sample of 30 papers from the Web of Science database was examined. We identified five broad categories of contributions: waste stream-derived production, combating food waste, strengthening soil health, and improving the efficiency of water resources. We concluded that, while manufacturing biosurfactants from waste streams can reduce production costs, optimizing yield remains a contentious issue that complicates the adoption of biosurfactants into the circular economy framework.

The present work aimed to investigate the efficiency of kinetic modeling and Response Surface Methodology (RSM), by employing a Central Composite Rotatable Design (CCRD) and to evaluate the effects of carbon and nitrogen sources, inoculation volume, and bioprocess time on an exopolysaccharide (EPS) producer, Klebsiella oxytoca ICCF 419, in batch fermentation with shaken flasks. Among the kinetic models tested, logistic equations were found to fit accordingly, with a correlation coefficient (R2 ) of 0.999. The interaction between glucose and corn steep liquor was found to have a significant impact on the EPS production, and glucose (2% w/v), and a 5% v/v inoculum of 24 hours age, are sufficiently to positively affect the bioprocess, if it is desired only a maximum cell growth, but not associated with the polymer synthesis. The optimal formula predicted by the RSM design was experimentally validated by the following results: 12.16 g EPS/L and 1.65 dry biomass/L, after 48 hours fermentation.