ORIGINAL RESEARCH article
Front. Microbiol.
Sec. Microbiotechnology
Volume 16 - 2025 | doi: 10.3389/fmicb.2025.1551264
This article is part of the Research TopicMetabolic Engineering and Synthetic Biology for Sustainable Microbial Cell FactoriesView all 3 articles
Microbial transformation of sewage sludge to biolipid-based fuel using potential oleaginous bacteria Streptomyces sp
Provisionally accepted
- 1Pir Mehr Ali Shah Arid Agriculture University, Rawalpindi, Punjab, Pakistan
- 2Allama Iqbal Open University, Islamabad, Islamabad, Pakistan
- 3Zhejiang University, Hangzhou, Zhejiang Province, China
- 4Department of Botany and Microbiology, College of Science, King Saud University, Riyadh, Saudi Arabia
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The high proportion of sludge generation worldwide has sparked interest in utilizing it for alternative purposes. Among different potential applications, using sludge as a substrate for oleaginous bacteria is a relatively novel approach. The study was conducted to harness Streptomyces sp. to produce biolipids and their further processing for biofuel through transesterification. Sewage sludge was obtained from the I-9 treatment plant, Islamabad; after initial characterization the unprocessed sludge was optimized viz: incubation time (24 to 96 h), inoculation rate (5 to 15%), pH levels (4 to 9), temperature (25 to 40°C), agitation (0 to 250 RPM), nitrogen sources (yeast, urea, ammonium chloride, and ammonium nitrate), and carbon sources (glucose, sucrose, starch, and dextrose). The maximum reactor performance was achieved with 40% lipid accumulation (gravimetric basis) in the dry cell biomass of Streptomyces sp. The qualitative analysis of the stored bio-lipids was performed using Fourier-transform infrared spectroscopy (FTIR) and Gas Chromatography-Mass Spectrometry (GC-MS). The results indicated the presence of C-H (Alkane), with additional phenolic and alcoholic bonds through FTIR, whereas the GC-MS results indicated the presence of palmitic acid and oleic acid as the most recurring compounds. This highlights the strong potential of Streptomyces sp. for biolipid-based fuel production using sludge as a substrate. Therefore, the contents of the extract (i.e. bio-lipids) were transesterified to produce biofuels from the stored lipids. The findings indicated the use of Streptomyces sp. potentially provides a dual benefit of reducing organic loading from the sludge along with biofuel production under optimized reactor conditions.
Keywords: Biodegradation, oleaginous bacteria, Streptomyces sp., sludge, transesterification
Received: 14 Jan 2025; Accepted: 22 Apr 2025.
Copyright: © 2025 Akbar, Anjum, Qadeer, Nawaz, Rao, Ullah and El-Tayeb. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence:
Muzammil Anjum, Pir Mehr Ali Shah Arid Agriculture University, Rawalpindi, 46000, Punjab, Pakistan
Zepeng Rao, Zhejiang University, Hangzhou, 310058, Zhejiang Province, China
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