Publications by authors named "Yopi"

Background: Actinomycetes isolated from marine habitats are known to have the potential for novel enzymes that are beneficial in the industry. In-depth knowledge is necessary given the variety of this bacterial group in Indonesia and the lack of published research. Actinomycetes isolates (BLH 5-14) obtained from marine sediments of Sarena Kecil, Bitung, North Sulawesi, Indonesia, showed an ability to produce pectinase and xylanase that have equal or even higher potential for pectic-oligosaccharides (POS) and xylooligosaccharides (XOS) production from raw biomass than from commercial substrates.

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  • Acidic and chemical stresses from lignocellulosic feedstock hinder effective lactic acid production, but using a strong yeast strain, Saccharomyces cerevisiae BTCC3, can overcome these challenges.
  • This engineered yeast demonstrated fast growth and high lactic acid productivity, achieving rates of 4.80 g L h under optimal conditions without needing detoxification or neutralization.
  • The research showed that using non-detoxified hydrolysate from sugarcane bagasse still yielded competitive lactic acid production, suggesting a simpler and more eco-friendly bioproduction method.
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Each year, the palm oil industry generates a significant amount of biomass residue and effluent waste; both have been identified as significant sources of greenhouse gas (GHG) emissions. This issue poses a severe environmental challenge for the industry due to the possibility of long-term negative effects on human well-being. The palm-oil industry must invest significantly in the technology that is required to resolve these issues and to increase the industry's sustainability.

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  • - The study explored how the yeast Lipomyces starkeyi can produce lipids using inexpensive sap from felled oil palm trunks as a carbon source, which has high sugar content (98 g/L glucose and 32 g/L fructose).
  • - Various fermentation conditions were tested using regular and enriched sap, achieving about 30 g/L of cell biomass and 60% lipid production under all conditions, even in acidic media (pH ≈ 3).
  • - The fatty acid profile of the lipids produced by L. starkeyi closely resembles that of palm oil, making it a potential sustainable feedstock for biodiesel, with oleic acid as the main fatty acid followed by palmitic, stearic, and
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A novel strategy for the low-cost, high-yield co-production of xylose and xylooligosaccharides together with no xylose inhibition was developed using a novel heterologous expression of XYN10Ks_480 endo-1,4-β-xylanase with a ricin-type β-trefoil type of domain and XYN11Ks_480 endo-1,4-β-xylanase with a CBM 2 superfamily from the Kitasatospora sp in an actinomycetes expression system. Xylose is the main building block for hemicellulose xylan. Our findings demonstrated high levels of expression and catalytic activity for XYN10Ks_480 during hydrolysis of the extracted xylan of bagasse, and three types of xylan-based substrates were used to produce xylose and xylooligosaccharides.

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  • - The study developed a budget-friendly method for producing bioethanol using a specific yeast strain (S. cerevisiae F118) and concentrated sweet sorghum juice, achieving a higher ethanol yield than a standard strain.
  • - The F118 strain achieved an impressive ethanol titer of 86.19 g/L, outperforming the non-flocculent BY4741 strain, which produced only 33.92 g/L, due to better gene expression linked to sugar processing.
  • - After multiple fermentation cycles, the F118 strain demonstrated successful separation from the liquid through floc formation, resulting in an ethanol concentration of 100.37 g/L by the fifth cycle.
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The addition of enzymes that are capable of degrading hemicellulose has a potential to reduce the need for commercial enzymes during biomass hydrolysis in the production of fermentable sugars. In this study, a high xylanase producing actinomycete strain (Kitasatospora sp. ID06-480) and the first ethyl ferulate producing actinomycete strain (Nonomuraea sp.

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Oleaginous microbes can convert substrates such as carbon dioxide, sugars, and organic acids to single-cell oils (SCOs). Among the oleaginous microorganisms, Lipomyces starkeyi is a particularly well-suited host given its impressive native abilities, including the capability to utilize a wide variety of carbon sources. In this work, the potential of L.

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  • The study focuses on generating glutathione directly from mannan-based materials using genetically modified yeast (Saccharomyces cerevisiae).
  • The researchers engineered the yeast to express specific enzymes that break down mannan, allowing it to efficiently convert mannose polysaccharides into glutathione.
  • They found that using locust bean gum, a cheap source of mannan, significantly boosted glutathione production, highlighting a potential eco-friendly method for bioproduction from such resources.
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Mannan endo-1,4-β-mannosidase (commonly known as β-mannanase) catalyzes a random cleavage of the β-D-1,4-mannopyranosyl linkage in mannan polymers. The enzyme has been utilized in biofuel production from lignocellulose biomass, as well as in production of mannooligosaccharides (MOS) for applications in feed and food industries. We aimed to obtain a β-mannanase, for such mannan polymer utilization, from actinomycetes strains isolated in Indonesia.

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Background: Mannans represent the largest hemicellulosic fraction in softwoods and also serve as carbohydrate stores in various plants. However, the utilization of mannans as sustainable resources has been less advanced in sustainable biofuel development. Based on a yeast cell surface-display technology that enables the immobilization of multiple enzymes on the yeast cell walls, we constructed a recombinant Saccharomyces cerevisiae strain that co-displays β-mannanase and β-mannosidase; this strain is expected to facilitate ethanol fermentation using mannan as a biomass source.

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A novel and extremely halophilic archaeon, designated strain 2a_47_2T, was isolated from a solar saltern sample collected in Indonesia. Cells of the strain were Gram-stain-negative, non-motile and pleomorphic and formed orange-red pigmented colonies. Strain 2a_47_2T grew at 20-48 °C (optimum 38-41 °C), pH 6.

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A novel halophilic archaeon, designated strain 2b_61_3T, was isolated from a solar saltern in Indonesia. Cells of the strain were Gram-stain-negative, motile, pleomorphic rods that formed orange-red-pigmented colonies on solid medium. The isolate grew optimally at 42-44 °C, pH 6.

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