No abstract

Selection of yeast for biomass production based on the cultivation results on whey. The objective of this research was to recommend a yeast species useful for biomass production in the form of single cell protein, using whey obtained form Turrialba cheese manufacturers as substrate. Three yeasts (Kluyveromyces marxianus, Candida kefyr and Saccharomyces cerevisiae) were grown separately in a batch fermentation system, and the fermentation time, total productivity and protein content of the biomass were determined. Significant differences (p<0.05) were found in the fermentation times required by each yeast. K. marxianus y C. kefyr respectively showed a fermentation time of 19 and 18 h, while S. cerevisiae needed 24 h. K marxianus showed a productivity of 0.22 g/Lxh, significantly different (p<0.05) from the productivities of C. kefyr and S. cerevisiae, with values of 0.14 g/Lxh and 0.13 g/Lxh, respectively. The protein content of the biomass for C. kefyr, S. cerevisiae, and K. marxianus were respectively of 34%, 35% and 32%. Considering the lowest time required for fermentation, the highest productivity and an equal content of protein in the biomass when compared to the other two yeasts, Kluyveromyces marxianus was chosen as the recommended yeast to produce single cell protein from cheese whey.

No abstract

On-farm trials were conducted to evaluate the potential of the System of Rice Intensification (SRI), a lowinput crop management system, to increase rice yields and reduce water consumption on subsistence farms in several regions of Panama and to determine how inherent soil fertility might affect SRI yields and the yield response to SRI management in the first season of SRI management. SRI practices increased yield by 47% on average and showed potential to increase yield by over 90%, while reducing water consumption by as much as 86%. SRI yields were correlated with available soil K and the difference between SRI and the conventional system yields was positively correlated with extractable Ca, Mg and Mn. The results of this study indicate that SRI is a promising rice production system for smallholder farmers in rural Panama farming under Panamanian soil conditions.