Damjan Vučurović

Having in mind current environmental challenges and depletion of resources, the sustainable development of bioprocesses represents an important strategy for advancing a circular, bio-based economy. The integration of biological systems and engineering principles enables the creation of production processes aligned with the principles of the circular economy. While optimizing bioprocess parameters at early stages of bioprocess development significantly enhances product yield and minimizes by-products, it also reduces waste. Optimization of process parameters, such as temperature, pH value, aeration and agitation rate, medium composition, etc., in accordance with the complex needs of the biocatalysts leads to environmentally sustainable and economically feasible production. Moreover, subsequent modelling and simulation of optimized bioprocesses enable scientists to observe and examine system behaviour through different scenarios and conditions. Bioprocess modelling and simulation serve as key tools for accelerating the transition from laboratory studies to pilot-scale and industry. The generated models follow the development of the bioprocess from its inception in the laboratory until the industrial plant start-up and validation, supplemented by data that become available as the scale increases. The integration of optimization, modelling and simulation techniques contributes to faster, more efficient bioprocess development while meeting modern sustainability and circular-economy requirements.

A significant proportion of workplace injuries are caused by inadequate maintenance of the workplace and it is important to understand the different causes of accidents and the control strategies that can be applied to reduce them. The key elements of risk control, i.e. the occupational safety and health management system, are planning, organization, control, monitoring and review. The listed elements of risk control include eliminating or reducing risks by using appropriate control measures and defined work practices, involving employees and supervisors in the planning process by defining responsibilities for workplace maintenance, recording all irregularities and work on maintenance and remediation of the workspace, as well as conducting regular safety audits of workplace maintenance procedures. A large percentage of workplace injuries are related to work with equipment. Protective measures to achieve the necessary reduction of risks when working with equipment include safety measures in the design of equipment that eliminate hazards or reduce risks for employees using the equipment, the provision of protective and/or complementary protective measures that take into account the use and reasonably foreseeable misuse of the equipment, as well as the provision of information for the use of work equipment.

Neurosurgery is undergoing a significant transformation driven by advances in biomaterials and tissue engineering. These interdisciplinary innovations address challenges in repairing and regenerating neural tissues, integrating cranial and spinal implants, and improving patient outcomes. The incidence of neurological injuries such as traumatic brain injury and spinal cord injury remains high, underscoring the need for improved therapeutic strategies. This review provides a comprehensive overview of current biomaterial and tissue engineering approaches in neurosurgery, highlighting developments in neural tissue repair, cranial and spinal implants, spinal cord injury treatment, and peripheral nerve regeneration. Key challenges—such as ensuring biocompatibility, modulating the immune response, and bridging the gap between laboratory research and clinical application—are discussed. Emerging technologies including 3D bioprinting, nanotechnology (removing microfluidics), and microfluidics are examined for their potential to revolutionize neurosurgical treatments. The need for interdisciplinary collaboration among neurosurgeons, material scientists, and biologists is emphasized as critical for overcoming translational barriers and accelerating the clinical translation of these promising technologies.

Bioethanol is a renewable, environmentally-friendly biofuel conventionally produced through the alcoholic fermentation of sugary or starch-rich substrates by microorganisms, commonly Yeast Saccharomyces cerevisiae. Intermediates of industrial wheat flour wet milling processing to starch, such as A-starch and B-starch milk, are cost-effective, abundant, and non-seasonal feedstocks for bioethanol production. This study evaluates the bioethanol production from wheat A-starch and B-starch milk and mixtures of these two substrates in different ratios (1:3, 1:1, and 3:1) using two cold hydrolysis procedures at 65 °C: (i) simultaneous liquefaction and saccharification (SLS) followed by fermentation, and (ii) liquefaction by alpha-amylase followed by simultaneous saccharification and fermentation (SSF). The results demonstrated that SSF and SLS are equally efficient procedures for reaching a high ethanol yield of 53 g per 100 g of starch and 93% of starch conversion to ethanol for all investigated substrates. Lower levels of non-starch components in A-starch milk, which typically contribute to volatile by-product formation, allowed clear distillate profiles in terms of and lower content of aldehydes, methanol, and volatile acidity, enhancing ethanol distillate purity compared to B-starch milk. Mixing high-quality A-starch milk with low-cost B-starch milk enables higher ethanol yield, improved distillate quality, and energy savings for efficient industrial-scale applications.

Xanthan is microbial polysaccharide with outstanding rheological properties, non-toxic nature, biodegradability, and biocompatibility. This biopolymer is widely used in food, biomedical, pharmaceutical, petrochemical, chemical and textile industry. Industrial xanthan production is generally conducted by aerobic submerged cultivation of Xanthomonas campestris strains on the media with glucose or sucrose under optimal conditions. Results from previous research indicate that xanthan can be successfully produced on media containing crude glycerol from biodiesel industry by different Xanthomonas species. The aim of this study was to examine the course of xanthan biosynthesis by the reference strain X. campestris ATCC 13951 in lab-scale bioreactor on medium containing crude glycerol generated in domestic biodiesel factory. The bioprocess was monitored by the analysis of cultivation medium samples taken in predetermined time intervals, and its success was estimated based on the xanthan concentration in the medium, separated biopolymer average molecular weight and degree of nutrients conversion. At the end of bioprocess, cultivation medium contained 12.34 g/L of xanthan with the average molecular weight of 3.04∙105 g/mol. Within this study, the achieved degree of glycerol, total nitrogen and total phosphorous conversion were 75.91%, 53.27% and 38.96%, respectively.

One of the key guidelines in the European waste management policy is the diversion of waste from landfills, preventing harmful effects on human health and the environment and ensuring that economically valuable waste materials are efficiently recycled and reused through proper management. The organic fraction of municipal waste is abundant and contains biodegradable ingredients such lignocellulose, starch, lipids, pectin, and proteins, making it suitable for biotechnological production. Taking into account that a large amount of organic waste is disposed of in landfills, within this work, the amount of organic waste disposed of in the landfill in Banja Luka was considered. Four simulation model scenarios of the integrated production of bioethanol and biogas are generated, and their process and economic aspects are discussed. In the first two modelled scenarios, the pretreatment conditions (1% sulfuric acid and a different neutralization agent) were varied, while in the other two, the share of the amount of raw material used for the production of bioethanol, i.e., biogas, was varied (split factor: 10–90%). The modelled plant, with a designed capacity of 6 tons/h of organic waste, is a significant bioethanol producer, generating 5,000,000 L/year. The profitability indicators, when examined, revealed that dedicating a portion of the organic municipal waste input exclusively to biogas production leads to decreased process efficiency. Based on the modeled process parameters, ethanol’s minimum feasible selling price is $0.6616 per liter, while regarding the composition of organic municipal waste, carbohydrates have the most significant impact on the viability of the process. The developed model represents an excellent basis for further development of this integrated bioprocess in such a way that it can be modified with new process parameters or economic or ecological indicators and used at all levels of bioprocess design. Additionally, the obtained sustainable integrated bioethanol and biogas production plant models could support forthcoming steps in municipal waste management by providing reliable data on the conditions under which the integrated process of bioethanol and biogas production would take place, as well as the technical feasibility and economic profitability of such organic municipal waste utilization.

The present work highlights the advances of integrated starch and bioethanol production as an attractive industrial solution for complex wheat exploitation to value-added products focusing on increased profitability. Bioethanol is conventionally produced by dry-milling wheat grain and fermenting sugars obtained by the hydrolysis of starch, while unused nonfermentable kernel compounds remain in stillage as effluents. On the other hand, the wet-milling of wheat flour enables complex wheat processing for the simultaneous production of starch, gluten, and fiber. The intermediates of industrial wheat starch production are A-starch milk, containing mainly large starch granules (diameter > 10 μm), and B-starch milk, containing mainly small starch granules (diameter < 10 μm). The present study investigates different starch hydrolysis procedures using commercial amylase for bioethanol production from A-starch and B-starch milk by batch fermentation using distillers’ yeast Saccharomyces cerevisiae Thermosacc^®. Cold hydrolysis with simultaneous liquefaction and saccharification at 65 °C, a pH of 4.5, and a duration of 60 min was the most efficient and energy-saving pretreatment reaching a high conversion rate of starch to ethanol of 93% for both of the investigated substrates. A process design and cost model of bioethanol production from A-starch and B-starch milk was developed using the SuperPro Designer^® v.11 (Intelligen Inc., Scotch Plains, NJ, USA) software.

The importance and interest in the efficient use and valorization of agro-industrial residues and by-products have grown due to environmental problems associated with improper disposal. Biotechnological production processes, including microbial biosurfactant production, represent a sustainable way to utilize agro-industrial residues and by-products, which are applied as substrates in these processes. Biosurfactants produced by microorganisms using renewable resources are a viable alternative to traditional petrochemical surfactants and have several potential uses in a wide range of industrial sectors due to their minimal ecotoxicity, easy biodegradability, and moderate production conditions. The common applications of biosurfactants, besides in food industry as food additives and preservatives, are in agriculture, environmental protection, the cosmetics and pharmaceutical industry, wastewater treatment, the petroleum industry, etc. This review aims to summarize the comprehensive scientific research related to the use of various agro-industrial residues and by-products in the microbial production of biosurfactants, as well as to emphasize the present state and the importance of their sustainable production. Additionally, based on the available biosurfactant market analysis datasets and research studies, the current situation in science and industry and the future perspectives of microbial biosurfactant production have been discussed.

In order to be competitive on the market, the production of biopreparations needs to be optimized, modeled and assessed in the early stages of its development. The aim of this paper was to optimize medium for the production of Trichoderma harzianum K179 biocontrol agent, to analyze its kinetics at enlarged laboratory scale and finally economic analysis of the production of this high-value product through simulation modelling. The results showed that the bioprocess of T. harzianum K179 bioagent production in a laboratory bioreactor on the medium with optimal composition (dextrose 10 g l⁻¹, soy flour 6.87 g l⁻¹, K₂HPO₄ 1.51 g l⁻¹, KCl 0.5 g l⁻¹ and MgSO₄ x 7H₂O 0.5 g l⁻¹), at stirring speed of 1.75 x g and aeration intensity of 1.5 vvm, can be shortened from 96 h to 36 h. The results of bioprocess economic analysis showed that with a 25-year project lifetime and investment payback time of 7.58 years, this project represents an economically viable system. Complete analysis of the bioprocess of Trichoderma harzianum K179 biocontrol agent production showed that the biologically produced preparation can be competitive on the market with synthetic preparations.

Microbial proteins, i.e., single-cell proteins or microbial biomass, can be cultivated for food and animal feed due to their high protein content and the fact that they represent a rich source of carbohydrates, minerals, fats, vitamins, and amino acids. Another advantage of single-cell proteins is their rapid production due to the growth rate of microorganisms and the possibility of using agro-industrial waste, residues and by-products for production through this renewable technology. Agro-industrial residues and by-products represent materials obtained from various processes in agriculture and agriculture-related industries; taking into account their composition and characteristics, as well as vast amounts, they have an enormous potential to generate sustainable bioproducts, such as microbial proteins. This review aims to summarize contemporary scientific research related to the production of microbial proteins on various agro-industrial residues and by-products, as well as to emphasize the current state of production of single-cell proteins and the importance of their production to ease the food crisis and support sustainable development.