No abstract

This work investigated fungal co-culture as inducer of ligninolytic enzymes and decolourising activity in the Colombian strain Leptosphaerulina sp., an ascomycete white-rot fungus isolated from lignocellulosic material. Aspergillus niger, Aspergillus fumigatus, Aspergillus terreus, Trichoderma viride, Fusarium sp. and Penicillium chrysogenum were tested as Leptosphaerulina sp. inducers. The best fungal combinations in terms of enzyme production, fungal growth and decolourising activity were selected from solid media experiments. Response surface methodology (RSM) was utilised to optimise enzyme production and decolourising activity in liquid media. Solid media assays evidenced T. viride and A. terreus as the best Leptosphaerulina sp. inducers. The RSM identified a triple co-culture inoculated with T. viride (1000 μL) and A. terreus (1000 μL) into a 7-day culture of Leptosphaerulina sp. as the best treatment. This triple combination significantly improved ligninolytic enzymes production and Reactive Black 5 dye removal when compared to the Leptosphaerulina sp. monoculture and previously used chemical inducers. These results demonstrated the potential of fungal co-culture as an environmentally-friendly method to enhance Leptosphaerulina sp. enzymes production and decolourising activity.

Polyhydroxyalkanoates (PHAs) are biodegradable and biocompatible plastics. They are synthesized by a wide variety of microorganisms (i.e., fungi and bacteria) and some organisms such as plants, which share characteristics with petrochemical-based plastics. The most recent studies focus on finding inexpensive substrates and extraction strategies that allow reducing product costs, thus moving into a widespread market, the market for petroleum-based plastics. In this study, the production of polyhydroxybutyrate (PHB) was evaluated using the native strains,Bacillus megaterium,Bacillussp., andLactococcus lactis, and glycerol reagent grade (GRG), residual glycerol (RGSB) byproduct of biodiesel from palm oil, Jatropha oil, castor oil, waste frying oils, and whey as substrates. Different bacteria-substrate systems were evaluated thrice on a laboratory scale under different conditions of temperature, pH, and substrate concentration, employing 50 mL of broth in 250 mL. The bacterial growth was tested in all systems; however, theB. megateriumGRG system generated the highest accumulation of PHA. The previous approach was allowed to propose a statistical design optimization with RGSB (i.e., RGSB, 15 g/L, pH 7.0, and 25°C). This system reached 2.80 g/L of PHB yield and was the optimal condition tested; however, the optimal biomass 5.42 g/L occurs at pH 9.0 and 25°C, with a substrate concentration of 22 g/L.

There are few reports on dual-purpose cattle systems characterization in Latin America and Colombia based on large datasets. This limits our understanding of their dynamics, and the establishment of public policies and government programs to improve their productive performance, promotion and rural development. This study aimed to characterize very small, small, medium, and large dual-purpose farms in Colombia from technical and environmental perspectives. The data analysed were obtained from the Ganadería Colombiana Sostenible and the LivestockPlus projects, which gathered information from a total of 1313 dual-purpose farms in Colombia. Farms were classified as being either very small (1 to 30 bovines), small (31 to 50 bovines), medium (51 to 250 bovines), or large farms (more than 251 bovines). Numerical and categorical variables were distributed into five components: (1) General Farm Information, (2) Herd Composition and Management, (3) Pasture Management, (4) Production Information, and (5) Environmental Information. Each component was analysed using the factorial analysis of mixed data (FAMD) method. According to FAMD, for the components General Farm Information, Herd Composition and Management, Pasture Management, and Production Information, the distribution of variables led to a spatial separation of the centroid from each category of producers. For the component Environmental Information, there was no separation of the centroid. In general, medium-sized and large farms showed better infrastructure, better machinery and equipment, and better reproductive practices; however, this was not reflected in a significant improvement of productive parameters, except for a lower mortality rate. Larger livestock producers need to plan their livestock husbandry activities properly, based on their better available infrastructure and livestock management practices, with the purpose of increasing productivity. The main features identified for each livestock producer category can be the basis to guide and establish policies and programmes for their technological development. The development of better livestock management practices and the implementation of technology, as well as technical assistance, should focus on small- and medium-sized livestock producers, which could lead to reaching a better productive and reproductive performance of dual-purpose systems.

In Colombia, cattle-fattening farms account for 20.7% of the Colombian cattle herd and play an important role in terms of economic and social benefits for rural communities. However, few characterization studies have been conducted on these production systems, which limit our understanding of their production dynamics and environmental impacts. This study aimed to characterize very small, small, medium, and large cattle-fattening farms from technical and environmental perspectives. The data analyzed were obtained from the Ganadería Colombiana Sostenible and the LivestockPlus projects, which gathered information from a total of 2618 farms, classified according to their cattle production orientation. From those, 275 cattle-fattening farms were classified as being either very small (1–30 bovines), small (31–50 bovines), medium (51–250 bovines), or large farms (more than 251 bovines). Numerical and categorical variables were distributed into five components: (1) general farm information, (2) composition and management of the herd, (3) pasture management, (4) production information, and (5) environmental information. Each component was analyzed using the factorial analysis of mixed data (FAMD) method. According to FAMD, for the components general farm information, herd composition and management, pasture management, and production information, distribution of variables led to a spatial separation of the centroid from each category of producers. For the component environmental information, there was no separation of the centroid. Better infrastructure, machinery and equipment, better pasture management, and better productive parameters and practices were observed in larger farms. This suggests that those public policies aimed at improving productive and environmental performance of the livestock sector should give priority to small- and medium-sized livestock producers considering their farm characteristics.