Aims: Palm kernel cake (PKC) is a high-protein, high-energy food that is widely utilized in the animal feed business. However, the high fibre and limited amino acid content of untreated PKC were the main issues for it to be used as animal feed, particularly in non-ruminants. To improve the quality of PKC, this study combined the use of solid-state fermentation (SSF) and consortia of fungi and bacteria to treat the PKC. Methodology and results: Two fungi, Emericella nidulans (4DP5) and Cladosporium herbarum (7DF12) and three strains of bacteria, Bacillus subtilis, which were active mannanase producers, were used in different combinations to reduce the hemicellulose content and improve the crude protein content of PKC in a lab-scale solid-state fermentation. PKC inoculated separately with five types of mixed culture treatments were allowed to ferment. The fermentation conditions were 20% inoculum (w/v), 85-92% humidity, pH 7.0 and PKC particle size 0.8 mm. PKC treatments with two fungi, E. nidulans (4DP5) and C. herbarum (7DF12), as well as a fungus-bacterium combination, E. nidulans (4DP5) and B. subtilis, outperformed the other three treatments. The crude protein levels were increased by 3.34% and 1.86%, respectively, due to these treatments. Furthermore, the level of aflatoxins produced increased marginally but remained within the permissible limits. Conclusion, significance and impact of study The treated PKC has more sugar and crude protein and less than 20 parts per billion (ppb) of aflatoxin, making it appropriate for animal consumption. The SSF technique of combining fungi and Bacilli enhanced the nutritional and market value of PKC substantially, which can be upscaled.
Aspergillus nidulans ; Cladosporium ; Bacillus subtilis ; Palm Oil ; Fermentation

Aims: Recent discoveries have revealed that Glaciozyma antarctica PI12 has been discovered to encode numerous protein-coding genes that are crucial for thermal adaptation. However, more than 35% of the protein-coding genes for this species were identified as hypothetical proteins (HP). Nevertheless, over 35% of the protein-coding genes for this species were classified as hypothetical proteins (HP). Previous studies have documented the role of these uncharacterized proteins in the physiological regulation and cold adaptation of psychrophilic microorganisms. Thus, we aim to identify the structural features of the conserved HPs that were ideal for their function in response to temperature stress. Methodology and results: Three conserved HPs of G. antarctica, designated GaHP2, GaHP3 and GaHP4, were cloned, expressed purified and their function and structure were evaluated. Functional analysis showed that these proteins maintained their activities at low temperatures below 25 °C, but at a lower reaction rate. Meanwhile, thermal unfolding assays revealed the stability of GaHP2 and GaHP4 at high temperatures (43 °C), suggesting their non-ATPbinding chaperone activity. The comparative structural analysis demonstrated that the HPs exhibited cold-adapted traits, most notably increased flexibility in their 3D structures. For GaHP2, the aromatic residues can be linked to its heat stability. GaHP4's cold shock domain implies it regulates gene transcription and translation during temperature fluctuations. Conclusion, significance and impact of study: This study has established the structure-function relationships of the G. antarctica HPs and provided fundamental experimental data highlighting their importance in thermal stress response by maintaining a balance between molecular stability and structural flexibility.

Aims: The search for new antibiotics is an ongoing effort and has expanded to pristine niche areas in the Antarctic in recent years due to the emergence of multi-drug resistant pathogens that outpaced the discovery of new antibiotics. We have recently isolated two new actinomycetes strains, INACH3013a and INACH3013b, which displayed antimicrobial properties from soil samples collected from Ardley Island, Antarctica. Hence, an investigation was carried out to identify them and to characterise the antimicrobial compounds produced. Methodology and results: Strains, INACH3013a and INACH3013b were identified based on their 16S rDNA sequence alignment to those in the GenBank. The results showed that strain INACH3013a was closest to Streptomyces spp. while strain INACH3013b was closest to Streptomyces corallincola and Streptomyces bullii. The extracellular compounds they produced were extracted using various solvents and the extracted compounds were tested against the test pathogens. The dichloromethane extracts from strains, INACH3013a and INACH3013b inhibited mainly Gram-positive pathogens that include Listeria monocytogenes, Staphylococcus aureus, Staphylococcus haemolyticus, Staphylococcus equorum, Bacillus cereus K3 and Enterococcus faecalis while extracts from strain INACH3013b also inhibited a Gram-negative pathogen, Klebsiella pneumonia 14x. Predominantly non-polar constituents seem responsible for antibacterial effects, with dichloromethane extracts proving most efficacious, followed by chloroform and ethyl acetate. Conclusion, significance and impact of study The research highlights the potential of Streptomyces spp. INACH3013a and INACH3013b as a source of potential novel antibiotics. This research explores Antarctic Streptomyces strains' antimicrobial capabilities, enabling the potential for the discovery of novel antibiotics and revealing how these compounds may have helped them to compete and survive in nutrient-deficient Antarctic niches.