Bioethanolic yeasts from dung beetles: tapping the potential of extremophilic yeasts for improvement of lignocellulolytic feedstock fermentation

Nwaefuna, Anita E; Rumbold, Karl; Boekhout, Teun; Zhou, Nerve

doi:10.1186/s13068-021-01940-y

Cited by 18 publications

(25 citation statements)

References 138 publications

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“…Termite guts harbour lignin-degrading bacteria belonging to varied genera such as Streptomyces, Pseudomonas, Bacillus and Sporothrix [ 129 ]. An extensive review of dung beetles by Nwaefuna et al, [ 131 ], also suggested that exploration of dung (excreta) of non-herbivores insects is becoming attractive in the search for ligninolytic microorganisms. Identification of ligninolytic consortia present in different animal guts is increasingly becoming easier using state-of-the-art high-throughput techniques [ 13 , 132 , 133 ].…”

Section: Ligninolytic Microorganisms From Other Animal Guts Other Tha...mentioning

confidence: 99%

Looking into the world’s largest elephant population in search of ligninolytic microorganisms for biorefineries: a mini-review

Rammala

Zhou

2022

Biotechnol Biofuels

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Gastrointestinal tracts (GIT) of herbivores are lignin-rich environments with the potential to find ligninolytic microorganisms. The occurrence of the microorganisms in herbivore GIT is a well-documented mutualistic relationship where the former benefits from the provision of nutrients and the latter benefits from the microorganism-assisted digestion of their recalcitrant lignin diets. Elephants are one of the largest herbivores that rely on the microbial anaerobic fermentation of their bulky recalcitrant low-quality forage lignocellulosic diet given their inability to break down major components of plant cells. Tapping the potential of these mutualistic associations in the biggest population of elephants in the whole world found in Botswana is attractive in the valorisation of the bulky recalcitrant lignin waste stream generated from the pulp and paper, biofuel, and agro-industries. Despite the massive potential as a feedstock for industrial fermentations, few microorganisms have been commercialised. This review focuses on the potential of microbiota from the gastrointestinal tract and excreta of the worlds’ largest population of elephants of Botswana as a potential source of extremophilic ligninolytic microorganisms. The review further discusses the recalcitrance of lignin, achievements, limitations, and challenges with its biological depolymerisation. Methods of isolation of microorganisms from elephant dung and their improvement as industrial strains are further highlighted.

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Section: Ligninolytic Microorganisms From Other Animal Guts Other Tha...mentioning

confidence: 99%

Looking into the world’s largest elephant population in search of ligninolytic microorganisms for biorefineries: a mini-review

Rammala

Zhou

2022

Biotechnol Biofuels

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“…The domestication and industrial applications of yeasts often depend on the natural genotypic and phenotypic variations that are characteristic of yeasts in their natural niches. Humans have tapped into the potential of feral yeasts to understand the biodiversity, ecology, and, most importantly, the diverse metabolic traits often associated with improved industrial production processes (Nwaefuna et al, 2021). The demand for new yeasts with unique and improved traits is evident in the fermentation industry, inclusive of the baking, brewing, winemaking, and bioethanol industries.…”

Section: Introductionmentioning

confidence: 99%

Diversity of dung beetle‐associated yeasts from pristine environments of Botswana

Nwaefuna

Boekhout

Vrhovšek

et al. 2023

Yeast

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Yeast-insect interactions are increasingly becoming an attractive source of discovery for previously unknown, unique, diverse, and industrially relevant yeast species. Despite a wealth of studies that have recently focused on yeasts in symbiotic association with Hymenopteran insects, yeasts associated with Coleopteran insects, such as lignocellulosic-rich dung-dependent beetles, remain poorly studied. Trends in yeast discovery suggest that species richness and diversity can be attributed to the ecological niche of the insect. Here, we considered the potential of dung beetles inhabiting the extreme environments of Botswana, characterized by desert-like conditions (semi-arid to arid and hot) as well as protected pristine environments, as possible attribute niches that can shape the extremophilic and diverse life history strategies of yeasts. We obtained a total of 97 phylogenetically diverse yeast isolates from six species of dung beetles from Botswana's unexplored environments, representing 19 species belonging to 11 genera. The findings suggest that the guts of dung beetles are a rich niche for non-Saccharomyces yeast species.Meyerozyma and Pichia were the most dominant genera associated with dung beetles, representing 55% (53 out of 97) of the yeast isolates in our study.Trichosporon and Cutaneotrichosporon genera represented 32% (31 out of 97) of the isolates. The remaining isolates belonged to Apiotrichum, Candida, Diutina, Naganishia, Rhodotorula, and Wickerhamiella genera (12 out of 97). We found out that about 62% (60 out of 97) of the isolates were potentially new species because of their low internal transcribed spacer (ITS) sequence similarity when compared to the most recent optimal species delineation threshold. A single isolate was unidentifiable using the ITS sequences. Using an in silico polymerase chain reaction-restriction fragment length polymorphism approach, we revealed that there was genetic diversity within isolates of the same species. Our results contribute to the knowledge and understanding of the diversity of dung beetleassociated yeasts.

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“…Maltose fermentation, in particular, is critical for yeast to leaven bread, yet it is a variable trait among and within yeast species (even within S. cerevisiae , the species commonly referred to as “baker's yeast” or “brewer's yeast”) (Naumov et al, 1994). Despite the ancient relationship between insects and yeasts, and the growing understanding that insects harbor yeasts which may be useful to various industries (Madden et al, 2018; Nwaefuna et al, 2021; Zhou et al, 2021), relatively little is understood about how these insights may be of use for targeted yeast discovery.…”

Section: Introductionmentioning

confidence: 99%

Sugar‐seeking insects as a source of diverse bread‐making yeasts with enhanced attributes

Madden

Lahue

Gordy

et al. 2021

Yeast

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Insects represent a particularly interesting habitat in which to search for novel yeasts of value to industry. Insect-associated yeasts have the potential to have traits relevant to modern food and beverage production due to insect-yeast interactions, with such traits including diverse carbohydrate metabolisms, high sugar tolerance, and general stress tolerance. Here, we consider the potential value of insect-associated yeasts in the specific context of baking. We isolated 63 yeast strains from 13 species of hymenoptera from the United States, representing 37 yeast species from 14 genera. Screening for the ability to ferment maltose, a sugar important for bread production, resulted in the identification of 13 strains of Candida, Lachancea, and Pichia species. We assessed their ability to leaven dough. All strains produced baked loaves comparable to a commercial baking strain of Saccharomyces cerevisiae. The same 13 strains were also grown under various sugar and salt conditions relevant to osmotic challenges experienced in the manufacturing processes and the production of sweet dough. We show that many of these yeast strains, most notably strains of Lachancea species, grow at a similar or higher rate and population size as commercial baker's yeast. We additionally assessed the comparative phenotypes and genetics of insect-associated S. cerevisiae strains unable to ferment maltose and identified baking-relevant traits, including variations in the HOG1 signaling pathway and diverse carbohydrate metabolisms. Our results suggest that non-conventional yeasts have high potential for baking and, more generally, showcase the success of bioprospecting in insects for identifying yeasts relevant for industrial uses. Take Away• We isolated yeasts from insects, identifying 63 strains of yeast from 14 genera.• Maltose fermentation was variable among species and strains.• Non-Saccharomyces yeasts leavened bread comparable to baker's yeast.• Insect-associated yeasts exhibited high osmotolerance and halotolerance.• Hymenoptera are a source for bioprospecting yeast for baking.

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Bioethanolic yeasts from dung beetles: tapping the potential of extremophilic yeasts for improvement of lignocellulolytic feedstock fermentation

Cited by 18 publications

References 138 publications

Looking into the world’s largest elephant population in search of ligninolytic microorganisms for biorefineries: a mini-review

Looking into the world’s largest elephant population in search of ligninolytic microorganisms for biorefineries: a mini-review

Diversity of dung beetle‐associated yeasts from pristine environments of Botswana

Sugar‐seeking insects as a source of diverse bread‐making yeasts with enhanced attributes

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