Strain improvement of native Saccharomyces cerevisiae LN ITCC 8246 strain through protoplast fusion to enhance its xylose uptake

Abstract

Co-utilization of xylose and glucose and subsequent fermentation using Saccharomyces cerevisiae could enhance ethanol productivity. Directed engineering approaches have met with limited success due to interconnectivity of xylose metabolism with other intrinsic, hidden pathways. Therefore, random approaches like protoplast fusion were used to reprogram unidentified mechanisms. Saccharomyces cerevisiae LN, the best hexose fermenter, was fused with xylose fermenting Pichia stipitis NCIM 3498. Protoplasts prepared using glucanex were fused under electric impulse and fusants were selected using 10% ethanol and cycloheximide (50 ppm) markers. Two fusants, 1a.23 and 1a.30 showing fast growth on xylose and tolerance to 10% ethanol, were selected. Higher extracellular protein expression observed in fusants as compared to parents was corroborated by higher number of bands resolved by twodimensional analysis. Overexpression of XYL1, XYL2, XKS and XUT4 in fusants as compared to S. cerevisiae LN as observed by RT-PCR analysis was substantiated by higher specific activities of XR, XDH and XKS enzymes in fusants. During lignocellulosic hydrolysate fermentation, fusants could utilize glucose faster than the parent P. stipitis NCIM 3498 and xylose consumption in fusants was higher than S. cerevisiae LN.

PENGOLAHAN JAMUR TIRAM (Pleurotus ostreatus) SEBAGAI PENYEDAP RASA ALAMI DENGAN METODE HIDROLISIS PROTEIN MENGGUNAKAN ENZIM DARI EKSTRAK NANAS (Ananas comosus)

“…Hidrolisat protein jamur tiram diperoleh dalam bentuk serbuk karena dilakukannya pemanasan dengan api sekitar suhu 100-105 °C untuk mengurangi kadar airnya. Pemanasan suhu tinggi dapat mendenaturasi protein sehingga menyebabkan perubahan struktur tersier protein, namun tidak mengalami perubahan susunan asam aminonya (Michel et al, 2006;Sharma et al, 2021). Pemanasan pada Suhu 70-80 °C menyebabkan aktivitas proteolitik dari enzim bromelin mengalami penurunan karena enzim menjadi inaktif atau berhenti bekerja, hal ini menyebabkan protein tidak mengalami proses penguraian lebih lanjut.…”

Multimedia Interaktif Model Neurosains dengan Transformasi Mode Daring dan Luring di Era New Normal

“…Salah satu pemanfaatan TIK dalam pembelajaran adalah pemanfaatan multimedia interaktif yang merupakan produk pembelajaran yang dapat mengubah materi abstrak menjadi konkret, dan dapat memberikan partisipasi aktif siswa dalam pembelajaran serta mampu mengatur interaksi antar siswa secara teratur, baik secara online. dan offline (Agustina, 2017;Sharma et al, 2021). Pembelajaran akan lebih efektif jika menggunakan model pembelajaran.…”

Editorial: Advances in Microbial Biofuel Production

“…Now-a-days, the bioenergy sector is not restricted to fuel production, but extends to biorefinery where other value-added products using waste/underutilized biomass are generated in order to make the overall process cost-effective ( Figure 1 ). Researchers are now addressing the fundamental issues of escalating fuel prices and depletion of fossil fuels through implementation of cost-effective bioenergy strategies (Sharma et al, 2018a , b , 2021 ).…”

“…Developing a robust methodology is a prerequisite requirement for quickly determining the suitability of any novel microbial strain or improvised strain toward bioenergy production (Sharma et al, 2021 ). For biodiesel production, oleaginous yeast strains are being explored and improved techniques are being employed for screening such strains.…”