Developing Microbial Co-Culture System for Enhanced Polyhydroxyalkanoates (PHA) Production Using Acid Pretreated Lignocellulosic Biomass

Rijuta Ganesh Saratale, Si Kyung Cho, Avinash Ashok Kadam, Gajanan Sampatrao Ghodake, Manu Kumar, Ram Naresh Bharagava, Sunita Varjani, Supriya Nair, Dong Su Kim, Han Seung Shin, Ganesh Dattatraya Saratale

Research output: Contribution to journalArticlepeer-review

14 Scopus citations

Abstract

In the growing polymer industry, the interest of researchers is captivated by bioplastics production with biodegradable and biocompatible properties. This study examines the polyhydrox-yalkanoates (PHA) production performance of individual Lysinibacillus sp. RGS and Ralstonia eutropha ATCC 17699 and their co-culture by utilizing sugarcane bagasse (SCB) hydrolysates. Initially, acidic (H2SO4) and acidified sodium chlorite pretreatment was employed for the hydrolysis of SCB. The effects of chemical pretreatment on the SCB biomass assembly and its chemical constituents were studied by employing numerous analytical methods. Acidic pretreatment under optimal conditions showed effective delignification (60%) of the SCB biomass, leading to a maximum hydrolysis yield of 74.9 ± 1.65% and a saccharification yield of 569.0 ± 5.65 mg/g of SCB after enzymatic hydrolysis. The resulting SCB enzymatic hydrolysates were harnessed for PHA synthesis using individual microbial culture and their defined co-culture. Co-culture strategy was found to be effective in sugar assimilation, bacterial growth, and PHA production kinetic parameters relative to the individual strains. Further-more, the effects of increasing acid pretreated SCB hydrolysates (20, 30, and 40 g/L) on cell density and PHA synthesis were studied. The effects of different cost-effective nutrient supplements and volatile fatty acids (VFAs) with acid pretreated SCB hydrolysates on cell growth and PHA production were studied. By employing optimal conditions and supplementation of corn steep liquor (CSL) and spent coffee waste extracted oil (SCGO), the co-culture produced maximum cell growth (DCW: 11.68 and 11.0 g/L), PHA accumulation (76% and 76%), and PHA titer (8.87 and 8.36 g/L), respectively. The findings collectively suggest that the development of a microbial co-culture strategy is a promising route for the efficient production of high-value bioplastics using different agricultural waste biomass.

Original languageEnglish
Article number726
JournalPolymers
Volume14
Issue number4
DOIs
StatePublished - 1 Feb 2022

Bibliographical note

Funding Information:
The authors would like to thank Dongguk University–Seoul, Korea, for supporting the research under a 2020–2022 research fund.

Publisher Copyright:
© 2022 by the authors. Licensee MDPI, Basel, Switzerland.

Keywords

  • Acid pretreatment
  • Co-culture strategy
  • Lysinibacillus sp. RGS
  • Polyhydroxyalkanoates production
  • Ralstonia eutropha ATCC 17699
  • Sugarcane bagasse

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