The versatility, contribution to sustainability, and diversity of applications of bacterial cellulose require large-scale production processes and new alternatives in terms of biological systems that, under controlled conditions, favor the growth and production of this biomaterial. This review article describes the technologies developed and the advances achieved in regard to the production of bacterial cellulose on a small and large scale, according to the findings evidenced in the scientific literature in the last ten years. A review, based on the guidelines in the PRISMA^® methodology, of a selection of articles was carried out, with a Cohen’s Kappa coefficient of 0.465; scientific databases, such as Web of Science, SCOPUS, PubMed, Taylor and Francis, and ProQuest, were considered. There is a wide variety of bacterial pulp production systems and the design of such a system is based on the type of cellulose-producing bacteria, oxygen requirements, mixing and agitation, temperature control, sterilization and cleaning requirements, and production scalability. The evolution in the development of bioreactors for bacterial cellulose has focused on improving the production process’s efficiency, productivity, and control, and adapting to the specific needs of bacterial strains and industrial applications.

Bacterial cellulose (BC) is emerging as an attractive large-scale polymer due to its superior properties. The dominant static culture for BC fermentation by bacteria or microbial consortium results in low productivity. Agitated culture, as an industrially projected technique, has been widely investigated but exclusively for cellulose-producing bacterial strains. Addressing this concern and evaluating the potential of residues as feedstock, this study highlights the utilization of microbial consortium BA2 and seven agro-industrial wastes including cocoa husks, sugarcane bagasse and others. Remarkably, rice bran (RB) appears as a promising substrate, achieving 2.14 g/L (dry basis) and outperforming the traditional HS medium, evident from a 15-day fermentation. A complex interplay between oxygen availability, glucose consumption and BC yield was revealed; while orbital and magnetic stirring with forced air ventilation (AFV) showed low BC yields and early biomass saturation, 4.07 g/L (dry basis) was targeted by magnetic stirring at 100 rpm from the start using only headspace air. However, beyond controlled operating conditions, mechanical agitation and favorable cellulose adhesion to metal in the stirred tank bioreactor negatively affect BC yield. This pattern uncovers the need for a further approach to the design of bioreactors when the microbial consortium is considered.

The production of craft beer depends on the quality and availability of yeast. However, many small breweries in developing countries face high costs due to their reliance on imported yeast strains. Developing efficient and low-cost propagation methods is therefore essential for sustainable production. A lager-type Saccharomyces cerevisiae strain (SC-Lager2) was propagated using both synthetic and low-cost alternative media. The latter was formulated with malt extract as a carbon source and yeast extract obtained from brewery by-products as a nitrogen source. A Plackett–Burman design identified significant factors influencing growth (p < 0.05), and a full factorial design (2⁴) optimized conditions. Growth kinetics and biomass yield were validated at laboratory (2 L) and pilot (83 L) scales. Maltose, yeast extract, zinc sulfate, and agitation significantly affected cell density and viability (p < 0.05). Under optimized conditions, 100% viability, a maximum cell density of 1.4 × 10¹⁰ cells/mL, and a biomass yield of 10 g/L were achieved values that were statistically higher (p < 0.05) than those obtained with the synthetic medium. The maximum specific growth rate (μ_max) increased by 52%, while doubling time decreased by 39%. Overall, the use of agro-industrial by-products reduced medium costs by approximately 65% compared to conventional synthetic formulations. The proposed low-cost medium provides a scalable, economical, and sustainable solution for yeast propagation, reducing production costs while maintaining high cell viability and performance. This approach supports the autonomy and competitiveness of the craft beer sector in developing regions.

Ganoderma lucidum is a widely studied fungal species due to its potential for producing mycelium-based biomaterials. In mycotecture applications, fungal mycelium colonizes organic substrates, forming composite structures that can be used as sustainable biomaterials. Meanwhile, the management of agro-industrial and wood residues remains an environmental challenge, as these materials are often discarded or burned. This study aimed to evaluate the effects of substrate composition and inoculum load on the recovered dry fraction obtained during the solid-state fermentation (SSF) of G. lucidum using brewer’s spent grain (BSG), an agro-industrial by-product of beer production, and sawdust, a wood-processing residue. An exploratory approach based on a reduced central composite design (CCD) was used to evaluate the effects of inoculum load and substrate composition on the recovered dry fraction. The apparent specific growth rate (µ) during the observed apparent exponential growth interval (days 3–6) and the corresponding doubling time (td) were also estimated. The treatment associated with the highest recovered dry fraction contained 40.13% (w/w) sawdust and 59.87% (w/w) BSG, with an inoculum load of 2.69% (v/w). Growth kinetics were subsequently estimated under these conditions. The apparent specific growth rate over days 3–6 was 0.6346 day⁻¹, corresponding to a doubling time of 1.0922 days. Substrate composition was the main factor associated with variation in the recovered dry fraction. These findings suggest that BSG and sawdust may be suitable substrate components for valorization through the SSF of G. lucidum. However, the recovered dry fraction is an operational measurement and should not be interpreted as a direct quantification of pure fungal biomass. The resulting specimens produced in this study exhibited a density of 0.24–0.27 g cm⁻³ and a compressive strength of 550–700 kPa.