Identification of microbial inhibitions and mitigation strategies towards cleaner bioconversions of palm oil mill effluent (POME): A review. (20th January 2021)

• Record Type: Journal Article
• Authors: Cheng, Yoke Wang; Chong, Chi Cheng; Lam, Man Kee; Leong, Wai Hong; Chuah, Lai Fatt; Yusup, Suzana; Setiabudi, Herma Dina; Tang, Yuanyuan; Lim, Jun Wei
• Is Part Of: Journal of cleaner production. Volume 280(2021)Part 1
• Publication Date: 2021-01-20
• Subjects: Oily effluent -- Wastewater valorization -- Biological treatment -- Microbial inhibition; Factory and trade waste -- Management -- Periodicals; Manufactures -- Environmental aspects -- Periodicals; Déchets industriels -- Gestion -- Périodiques; Usines -- Aspect de l'environnement -- Périodiques; 628.5
• DOI: 10.1016/j.jclepro.2020.124346
• Languages: English
• ISSNs: 0959-6526

Abstract

Abstract: Flourishing oil palm agroindustry inevitably produces voluminous pollutant-laden palm oil mill effluent (POME), which often treated by obsolete open ponding. By introducing foreign microbes, POME bioconversions confer simultaneous valorization and remediation of POME; however, environmental-sensitive microbes are prone to microbial inhibitions, which can upset the bioconversion. Herein, up to eight possible microbial inhibitions of POME bioconversions are identified and detailed after holistic review of multitudinous bioconversion routes. Potential microbial inhibitions include oil encapsulation, chemical inhibition, physical disruption, strict oxygen preference (O2 toxicity/deficiency), extreme temperature (cold/thermal denaturation), extreme pH (acid/alkali toxicity), extreme salinity, and photoinactivation. To lessen microbial inhibitions in POME bioconversions, constructive mitigation strategies are classified into three aspects, viz. substrate aspects (debris removal, supplementation, dilution, pretreatments, & co-substrates addition), microbial aspects (mixed cultures, immobilization, granulation, & gradual acclimation), and process aspects (thermophilic anaerobic/mesophilic aerobic pairs, continuous operation, pH control/adjustment, biosludge recycling/entrapment, & additional bioreactor). In authors' opinion, genetically modified microbes (GMM) application in POME bioconversions might be a promising research direction. Aforesaid superbugs can be engineered for efficient bioremediation, rapid proliferation, and high adaptability, which likely resolve all the aforesaid microbial inhibitions via genetic engineering. Graphical abstract: Image 1 Highlights: Biological-based POME prevalent treatment is inefficient without foreign microbes. POME bioconversion introduces foreign microbes to intensify POME degradation. POME bioconversions offer tailorable bioproduct formation via diverse pathways. Environmental-sensitive microbes are prone to eight types of microbial inhibition. Possible mechanisms and mitigation strategies of microbial inhibition are detailed.