Colony Shape Research Articles

Isolation and Molecular Identification of Lactic Acid Bacteria from Robusta Coffee Fermentation and Antifungal Test against Penicillium sp.

Lactic acid bacteria (LAB) play an important role in robusta coffee fermentation by soaking coffee beans. Spontaneous fermentation of coffee beans can improve coffee quality by producing organic acids and volatile compounds. The ability of LAB to produce organic acids also has the potential as an antifungal compound. Penicillium is one of the predominant contaminants of coffee beans products in Indonesia. Coffee beans can become contaminated by Penicillium during various stages such as harvesting, processing, transport, and storage. To prevent contamination of coffee beans, new preservation methods involving biological agents, such as lactic acid bacteria, may be used instead of chemicals. The secondary metabolites produced by LAB can be utilized for bio preservation. Lactic acid bacteria in robusta coffee fermentation should be further explored and analyzed for antifungal activity against Penicillium sp., and molecularly identified to determine the spesies of lactic acid bacteria that have antifungal potential. The isolation method was carried out using multilevel dilution and spread plate on MRSA+CaCO3 media. Identification was conducted through macroscopic and microscopic observation of cells and their characteristics, as well as molecular identification. Antifungal testing was performed using the agar well diffusion method. The results of LAB isolation yielded 12 LAB isolates with characteristics of round colony shape, gram-positive, rod and round cell shape, with negative catalase. The test results showed that isolates BKR 4, BKR 11, BKR 12 exhibited antifungal activity. BKR11 isolate was identified as Leuconostoc mesenteroides.

Chain or sphere? Perspectives on colony shapes and sizes in microalgae

Abstract Some microalgal species can increase their collective size by forming colonies; notable examples are chained colonies in diatoms and Scenedesmus sp., and spherical colonies in Phaeocystis globosa. For a given cell-specific growth rate, chain formation increases collective length quickly to fend off ciliates, but not against tube- and pallium-feeding heterotrophic dinoflagellates or metazoan grazers with ability to manipulate chains to aid ingestion. Sphere increases in volume relatively slowly but would be difficult to manipulate even for metazoan grazers. Diffusive nutrient supply to a chained colony would be a fixed proportion of that to solitary cells, regardless of chain length, whereas cells within a spherical colony would experience increasing nutrient limitation with increasing colony size. One hemisphere of a spherical colony would inevitably receive less irradiance, creating an auto-light limitation. Experimental data showed that light decreased substantially as it passed through a P. globosa colony, and the optical density of the colony increased linearly with colony diameter. However, neither in situ nutrient nor light limitation alone can explain an order-of-magnitude difference in colony size between the European and the Asian P. globosa populations. Instead, some evidence of different expression of gene(s) involved in colony formation and enlargement suggests genomic variations among the different populations.

CHARACTERIZATION AND IDENTIFICATION OF SM4 BACTERIAL ISOLATE FROM Stylissa massa SPONSE AS PRODUCING ANTIMICROBIAL COMPOUNDS AGAINST PATHOGENIC BACTERIA

East Nusa Tenggara (NTT) is one of the archipelagic provinces in Indonesia with a sea area of 200,000 km² and contains potential marine resources including the Stylissa massa sponge. Bacteria have been known to associate with sponges and have the ability to produce antimicrobial compounds. This study aims to characterize, identify the 16S rRNA gene, and test the bioactive compounds of SM4 bacterial isolates from the Stylissa massa sponge. The bacterial isolates of SM4 were previously rejuvenated on NA medium, then characterized by macroscopic morphology, and biochemistry by citrate test and TSIA test. The culture was extracted using petroleum ether solvent and the antibacterial activity was tested against E. coli and S. aureus by the well method. The isolates were then identified based on the 16S rRNA gene by PCR method. The results showed that, SM4 isolates had small colony size, yellow color, round colony shape, flat elevation, flat margins, while biochemically they had positive results with Citrate and TSIA tests. The antagonist test of the SM4 bacterial isolate was found to have the ability to inhibit the growth of S. aureus and E. coli, while the antibacterial activity test of the bioactive compound bacterial isolate SM4 was known to have the ability to inhibit the growth of S .aureus with an inhibition zone of 1.99 mm and E. colli 1.56 mm. The results of the molecular identification of the bacterial isolate SM4 had 99% similarity with the Bacillus cereus strain Nr_074540.1

Beyond Caster as object? Examining media constructions of Caster Semenya through decolonial thinking

ABSTRACT The popular media coverage of South African track and field star Caster Semenya showcases how colonialist discourses shaped the sexed, gendered, and racialised meaning of her public biography. Yet, when researchers study Semenya as their research ‘object’, does this act of inquiry reproduce the knowledge constructs of Western coloniality as well? In this article, we consider both issues by conducting and reflecting on our poststructuralist analysis of popular media coverages of Semenya’s athletic career, with specific attention to her dealings with gender-verification testing. We examine the discursive construction of Semenya’s public biography by popular newspaper outlets in the United States and South Africa from 2009 to 2019, arguing that both geopolitical locales maintained Western social binaries and scientific discourses concerning Semenya’s sexual identity in similar, yet distinct ways. Drawing from the poststructuralist methodology of intertextuality, we reflect on its capacity to deconstruct the colonial discourses shaping the cultural meaning of a non-Western athlete of colour such as Semenya, as well as its relation, as a method of knowledge production, to the epistemological legacies of Western coloniality. We also contend that by approaching Semenya as the ‘object’ of our poststructuralist framework, our analysis implicitly reproduced, rather than challenged, the Eurocentric subject/object framework of modern (Western) epistemology. Thus, our purposes are empirical, methodological, and reflexive as we seek to contribute to critical analyses of the constructed cultural meaning of celebrity athletes while subjecting our own research assumptions and frameworks to poststructuralist and decolonial deconstruction.

Isolasi, Skrining, dan Identifikasi Molekuler Bakteri Termotoleran Proteolitik dari Sumber Air Panas Nglimut Gonoharjo Kendal

The potential for the use of enzymes in industry is starting to be widely used. Protease is one of the most widely used enzymes in industry. Protease is an enzyme capable of hydrolyzing peptide bonds in proteins. Proteolytic thermotolerant bacteria are one of the important sources of thermostable enzymes that can be isolated from hot springs. The purpose of this study was to isolate and screen proteolytic thermotolerant bacteria and to identify molecularly the best isolates of proteolytic thermotolerant bacteria from the hot springs of Nglimut Gonoharjo. Isolation was carried out by graded dilution on Sodium Agar (NA) and Thermus Agar (TA) media using the spread plate method, and the proteolytic activity test using the paper disc method. Characterization of proteolytic bacterial isolates was carried out by macroscopic and microscopic morphology with gram staining. Molecular identification with 16S rRNA gene through amplification, electrophoresis, sequencing, BLAST analysis and phylogenetic reconstruction. The isolation results obtained 32 proteolytic thermotolerant isolates with irregular and round colony shape characteristics, Gram positive and Gram negative, and stem cells. The results of the enzyme test showed that isolate T5 was the best isolate with a proteolytic index value of 1.90 and was identified as Bacillus subtilis. Gram Positive and Gram Negative, and have stem cells. The results of the enzyme test showed that isolate T5 was the best isolate with a proteolytic index value of 1.90 and was identified as Bacillus subtilis.

Factual Power Loss Lessening by Enhanced Synthetic Biome Optimization and Green Algae Algorithms

In this paper Enhanced Synthetic Biome Optimization (ESBO) and Green Algae algorithm (GAA) is designed to abridge the power loss. Synthetic Biome Optimization (SBO) algorithm is a nature-inspired optimization algorithm, stimulated by the stream of energy in a biome on the world. The biome can be enunciated as a cluster of existing entities living in a certain province and the biome outlines the associations among them. The deprived entity (creator) is rationalized by the upper and low borders of exploration space and the pre-eminent entity (putrefaction). Levy flight applied to augment the exploration and imitate the food probing process of many faunae. In order to augment the convergence characteristics of the SBO algorithm, sine-cosine functions has been incorporated in the technique. This augmentation will stimulate divergent solutions and modifies in the direction of the distinguished prospective solution in ESBO. Proposed GAA approach imitates growing, reproduction deeds of green algae in sunlight. Green algae live in the shape of algal colonies which consist of algal cells. When green algae in least amount of sunlight it will be small size, energy and particularly starvation level will be high, but it will attempt to acclimatize by using adaptation probability in the ambiance where it positioned. Enhanced Synthetic Biome Optimization and GAA appraised in IEEE 57 and 300 bus systems. Assessment with other techniques has been done. Projected ESBO and GAA approaches abridged the power loss meritoriously

Characterization and bio-efficacy of entomopathogenic Beauveria associated with cuticle-degrading enzymes to restrain sucking pest Bemisia tabaci.

The entomopathogenic Beauveria spp. were acquired from insect cadavers and soil rhizosphere of cotton, groundnut, and castor. Among Beauveria, five spp. derived from infected insects, eight Beauveria found from soil, and one strain of Beauveria bassiana collected from MTCC 9544. Beauveria were characterized for morphology and cuticle-degrading enzyme activity associated with virulence against Bemisia tabaci. The colony morphology, conidial arrangement, size, and shape confirmed all isolates as Beauveria. The chitinase (EC 3.2.1.14) and lipase (EC 3.1.1.3) activities were observed the highest in Beauveria JAU2, while higher protease (EC 3.4.21.4) activity found in JAU4 followed by JAU2 at 240h. The bio-efficacy of Beauveria (1 × 107 conidia.ml-1) illustrated that potent JAU2 was examined with the highest % mortality and corrected mortality of B. tabaci at 144h followed by JAU1. The LC90 and LC50were determined from potent (JAU1 and JAU2) and weak (JAU6), and it was found the lowest in JAU2. The most potent Beauveria JAU2, isolated from insect cadaver (Harmivora armigera), was illustrated higher virulence than other isolates. The Beauveria JAU2 were recognized as Beauveria bassiana based on the shape of conidia and size (2.00 to 2.09µm dia) as examined in SEM. Study insight into recognition of potent Beauveria bassiana JAU2 was linked with cuticle-degrading enzyme activity for insecticidal action. The JAU2 isolate established the most positive correlation (P0.01: 0.864) between chitinase activity and corrected mortality of insect.

Predator Field and Colony Morphology Determine the Defensive Benefit of Colony Formation in Marine Phytoplankton

Colony formation in marine phytoplankton can be modified by the presence of grazers, but the effect of colony size and shape on the feeding behavior of grazers is still relatively unknown. To explore the defensive role of colony formation, we examined the feeding response of three differently sized grazers (copepodites, copepod nauplii, and two heterotrophic dinoflagellates) feeding on colony-forming phytoplankton, using both direct video observations and bottle incubations. We found a dramatic increase in capture clearance rate with colony size for copepodites, up to 140% higher in the largest diatom chains relative to their solitary cells. This was in part facilitated by a mechanism – described here for the first time – by which copepods efficiently detect and capture colonies using the antennules, thereby increasing their capture radius. Prey handling time by copepodites increased with colony size, but did not limit prey ingestion. Larger chains of diatoms were efficiently handled and consumed by the copepodites, whereas larger spherical colonies of Phaeocystis globosa were rejected subsequent to capture. In contrast, colonial phytoplankton were better protected against the microzooplankton and copepod nauplii examined, since these only managed to consume smaller colonies equivalent of a few cells. We find that the defensive value of colony formation depends on the size and foraging behavior of the grazer and the size and shape of the colony. Thus, the defensive benefit is therefore a function of the composition of the grazer community. We argue that bloom formation in chain-forming diatoms is facilitated by the efficient protection against rapidly responding micro-grazers and the lagged numerical response of efficient copepod grazers.

Indigenous Women's Resistance of Colonial Policies, Practices, and Reproductive Coercion.

This analysis of urban Indigenous women’s experiences on the Homeland of the Métis and Treaty One (Winnipeg, Manitoba, Canada), Treaty Four (Regina, Saskatchewan, Canada), and Treaty Six (Saskatoon, Saskatchewan, Canada) territories illustrates that Indigenous women have recently experienced coercion when interacting with healthcare and social service providers in various settings. Drawing on analysis of media, study conversations, and policies, this collaborative, action-oriented project with 32 women and Two-Spirit collaborators demonstrated a pattern of healthcare and other service providers subjecting Indigenous women to coercive practices related to tubal ligations, long-term contraceptives, and abortions. We foreground techniques Indigenous women use to assert their rights within contexts of reproductive coercion, including acts of refusal, negotiation, and sharing community knowledge. By recognizing how colonial relations shape Indigenous women’s experiences, decision-makers and service providers can take action to transform institutional cultures so Indigenous women can navigate their reproductive decision-making with safety and dignity.

Colonial Roots of Modern Development Discourse

The paper is structured around a thesis that the historical and colonial roots of modern development shape contemporary development themes and discourses, and that these in turn influence the metrics and indicators used to measure development. The article looks into how colonial relations shape contemporary development themes; the historical evolution of the key themes and measurements of development; finally, how various important “developers,” particularly multilateral and bilateral development agencies, use their epistemic privilege to influence the metrics or indicators that we use to measure development, with particular emphasis on the measures of poverty and inequality. The paper uses a historically grounded narrative structure in demonstrating how colonial legacies have continued to influence development discourse and the related metrics and indicators used in development theory and practice. Finally, the author identifies future avenues of research, particularly how metrics or measures might correspondingly shape emerging development themes and discourses.

Islands of Integration or Islands of Marginality? Dynamics of Belonging and Otherisation in the Sahelian Chad

ABSTRACT Histories of othering through race, ethnicity, or other forms of belonging follow context-specific trajectories. Building on nine months’ fieldwork in Chad, this article engages with discussions about othering in postcolonial Africa. The article moves from the description of micro-divisions in the Guéra province, in the Chadian Sahel, to discuss theoretical paradigms connecting African discourses on race and ethnicity to precolonial cleavages or colonial divisions, and theories that connect emerging ideas of autochthony with neoliberal reforms of governance. It shows that both precolonial cleavages and colonial shaping of identities were contradictory and remain important because of their use by French colonial and Chad postcolonial governments to divide and rule local people. This has fostered forms of political competition based on othering further reinforced by neoliberal reforms of local governance. The increasing dynamics of othering are not therefore specific to Guéra’s cleavages but connected to divisive forms of governance.

Identification And Detection Of Proteolytic Activity Of Endophite Bacterial Isolated From Avicennia Marina Leaves In Mempawah Mangrove Center

Abstract. Endophytic bacteria are bacteria that live in healthy plant tissue without damaging the plant tissue itself. This study aims to determine the morphological and physiological characteristics, as well as to determine the proteolytic activity of the genus of endophytic bacteria found in Avicennia marina leaves. The research was conducted through the stages of bacterial isolation, morphological characterization, physiological test which includes biochemical factor test and proteolytic activity test, as well as identification. The method used is a systematic sampling method and the data collected were analyzed descriptively. The characteristics of endophytic bacteria obtained have morphological characteristic with rounded colony shapes, flat and wavy edgs, convex elevation, white to yellow colony color, gram positive and negative with cocci and bacillary cell shapes. Physiological tests on the salinity, pH and temperature tests of all isolates produced a positive reaction. The results obtained 6 isolates of endophytic bacteria from Avicennia marina leaves which have similarities with members of the genus Staphylococcus, Bacillus, Pseudomonas and Micrococcus. The isolates obtained did not have proteolytic activity.

Individual based simulations of biofilm dimensional transitions

Microbial biofilms are important actors in many different environments. They can be harmful, e.g., on medical implants or in industry settings, as well as beneficial, e.g., in the human gut or on plant roots. In different experimental situations, we find a great variety of two-dimensional and three-dimensional colony shapes, but the underlying principles are not always clear. Here, we present a three-dimensional individual based model of spherocylindrical bacteria that initially grow and divide on a flat surface, but can also move into the third dimension.

Variability and Virulence Analysis of Aspergillus niger Isolates Causing Collar Rot of Groundnut

Background: Collar rot of groundnut (Arachis hypogaea L.) caused by Aspergillus niger is a significant constraint in groundnut cultivation and responsible for huge economic losses in India including Rajasthan. Methods: By surveying of eight major groundnut growing districts of Rajasthan, India, one representative Aspergillus niger isolate from each district was established (ANBK-01= Bikaner, ANCH-02= Churu, ANDA-03= Dausa, ANJP-04= Jaipur, ANJL-05= Jalore, ANJD-06= Jodhpur, ANNG-07= Nagaur and ANSK-08= Sikar) for studying variability in the pathogen as well as to know the response of groundnut varieties to the highly virulent isolate. The colony and spore characteristics were observed for cultural and morphological variability. For resistance response to the disease, ten varieties (M-13, RG-633-9, RG-382, Girnar-2, RG-604, RG-578, Gajraj 10, RG-510, RG-632-1 and RG-644) were evaluated in the field for two consecutive years against a highly virulent Aspergillus niger (ANJP-04) isolate. Result: Our investigations cleared that all the isolates were showed cultural and morphological variability such as shape, colour and size of colony and size of conidia, conidiophores and columella. Isolate (ANJP-04) collected from Khejroli village of Chomu tehsil in Jaipur district showed maximum mycelial growth, conidia diameter, length and diameter of conidiophores and length and diameter of columella, early sporulation and found most virulent as it produced higher disease incidence (54.43%). Ten released varieties of groundnut in the field conditions, revealed that none of the variety was found completely free from the disease whereas RG-644, M-13 and RG-510 were found resistant while RG-604, Girnar-2, Gajraj-10 and RG-632-1 were found moderately resistant and rest were found susceptible to highly susceptible to the disease. Conclusively, it can be finalized that famers may cultivate these resistant varieties in areas where collar rot is a severe constraint. The conclusion of this study can also be utilized to screen varieties/genotypes of groundnut against highly virulent isolate for sustainability of breeding material to the disease effectively.

Characteristics of fungi contaminant in tissue culture of Bromheadia finlaysoniana (Lind.) Miq

Generative propagation of orchid plants has problems because orchid seeds do not have endosperm that need to be multiplied using tissue culture. Contamination is a limiting factor in the multiplication of plants in tissue culture. This study describes the types of contaminants found in Bromheadia finlaysoniana callus. This research was carried out in two stages. The first stage is carried out culture of various explants of Bromheadia finlaysoniana using murashige and Skoog media with enrichment of hormone Benzylaminopurine 1 mg/l; (Naphthalene acetic acid) 0.5 mg/l; 100 mg mynositol; pyridoxine-HCl 0.5 mg/l; thiamine-HCl 0.1 mg/l; nicotinic-acid 0.5 mg/l; glycine 2 mg/l. The second stage is observed and the percentage of contaminant fungi. The observed contaminants character includes the colour, the direction of growth, and the hyphae colony's shape. Determination of contaminants type compared to the morphology of references. The result is the highest contamination in flower stalk explants, 81%; most colonies on leaf explants are 28. Contaminant fungi grow predominantly of fungi with white and grey colour and a rough surface shape. The macroscopic character of contaminant fungi in tissue cultures mostly comes from the class of Deuteromycetes and Zygomycetes. Keywords: Bromheadia finlaysoniana , contaminant, fungi, tissue culture

Prevalence, Intensity, and Morphological Variability of Wheat Blotch (Zymoseptoria tritici) in Oromia, Ethiopia

Studies of the wheat Zymoseptoria tritici blotch (ZTB) status in different locations, on agronomic practice, and pathogen variability has not yet been studied in Ethiopia. As a result, the goal of this study was to determine ZTB's distribution and intensity, as well as the morphological variability of isolates. In Oromia's central-southeastern region, zones and districts were purposefully chosen, whereas kebeles were determined via a systematic sampling procedure. In a generalized linear model (GLM), the mean comparison of fixed effects was examined using least significant difference (LSD) tests. Colony texture, shapes, and colors were used to identify isolate variability. Pearson correlation was used to examine the relationship between disease intensity and the independent variable, and multiple regression analysis was used to estimate the magnitudes of the association. A total of 108 fields were examined, with the percent occurrence of zones (88.9 to 100%) and districts (77.8 to 100%) recorded. ZTB intensity was not significantly different across districts (p 0.05) while severity was significantly different across zones (p 0.01). Weed infestation (r = 0.78 and r = 0.20) and growth phases (r = 0.72 and r = 0.36) had a positive correlation, although plowing frequency (r = -0.77 and r = -0.43) had a negative correlation with incidence and severity. There are 43 isolates classified into four colors, three textures, and three growth forms. The ZTB epidemics in current research areas are need more consideration and they should be prioritized for integrated management. Our data suggest that weed control, soil tillage, and crop rotation are all effective ways to mitigate the effects of wheat ZTB.

Extractive governmentality, ethnic territories, and racial imaginaries in the northern Amazon of Ecuador

This article analyzes the essentialization of ethnic difference, or racialization, in processes of extractive governmentality and ethnic territoriality in the upper Amazon Region of Ecuador. I trace contemporary and historical colonial legacies shaping land and oil compensation disputes among Kichwa families in Pañacocha. I argue that extractive governmentality uses legal and institutional frameworks based on multicultural and clientelist principles that appear to benefit populations based on ethnic and cultural difference. However, I show that this approach exacerbates colonial understandings of ethnic difference, generating conflicts among Indigenous families.First, I show that oil legal frameworks, and ethnic territorial frameworks obscure the existence of ethnic diversity within Indigenous territories, forcing families to choose between essentialized Indigenous and non-indigenous backgrounds to secure territory, access to oil compensations, and state development programs. Legal and institutional frameworks continue to further racial colonial divides and hierarchies between Indigenous territories and the rest of society. Second, these legal and institutional frameworks have empowered a group of Indigenous leaders that act as power-brokers between territories and the state. Indigenous leaders distance themselves from the rest of families by strategically aligning with their Kichwa, colono, and mestizo ethnic and cultural backgrounds as convenient. This way leaders exclude families from participating in territorial governance either because they are too Indigenous to understand territorial projects paid for with oil profits, or because they are not Indigenous enough to be considered part of the territory.

Prevalensi Bakteri Methicillin-Resistant Staphylococcus aureus (MRSA) Pada Peralatan Laboratorium

Staphylococcus aureus bacteria are common flora bacteria that are both commensal and opportunistic pathogens in humans. They are commonly treated with antibiotics, which can lead to bacterial resistance, such as the emergence of Methicillin-Resistant Staphylococcus aureus (MRSA) bacteria, which are resistant to the β -lactam antibiotics that are currently widespread to a variety of communities, such as the campus community, which is equipped with several facilities such as laboratories. The microbiology laboratory is a practicum and research laboratory that uses materials in the form of microorganisms, hence it has the potential to transmit MRSA bacteria. The aim of this study is to find out if MRSA bacteria are present on microbiology lab equipment and how prevalent they are. This study used observational research with a descriptive research design and a purposive sampling strategy. The results of bacterial isolation on MSA medium from fourteen laboratory equipment revealed that thirteen devices exhibited bacterial growth, whereas one device had none. Seven bacterial isolates with S. aureus-like features are detected growing in three of the thirteen equipment, the LAF, incubator, and manual autoclave. The seven bacterial isolates were identified as having round colony shape, glistening, opaque, convex yellow pigmentation, round cell morphology, clustered like grapes and purple in color, positive for coagulase and catalase, and resistance to methicillin antibiotics (MRSA bacteria). It can be concluded that of the fourteen-laboratory equipment examined, three instruments, namely the LAF, incubator, and manual autoclave, were found to be overgrown with MRSA bacteria, with the prevalence of MRSA bacteria in microbiology laboratory equipment reaching 21.4%. Keywords: laboratory equipment, MRSA, prevalence, S. aureus

Ecological adaptation and phylogenetic analysis of microsymbionts nodulating Polhillia, Wiborgia and Wiborgiella species in the Cape fynbos, South Africa

Polhillia, Wiborgia and Wiborgiella species are shrub legumes endemic to the Cape fynbos of South Africa. They have the ability to fix atmospheric N2 when in symbiosis with soil bacteria called ‘rhizobia’. The aim of this study was to assess the morpho-physiological and phylogenetic characteristics of rhizobia associated with the nodulation of Polhillia, Wiborgia and Wiborgiella species growing in the Cape fynbos. The bacterial isolates from root nodules consisted of a mixture of fast and intermediate growers that differed in colony shape and size. The isolates exhibited tolerance to salinity (0.5–3% NaCl) and pH (pH 5–10) and different antibiotic concentrations, and could produce 0.51 to 51.23 µg mL−1 of indole-3-acetic acid (IAA), as well as solubilize tri-calcium phosphate. The ERIC-PCR results showed high genomic diversity in the rhizobial population and grouped them into two major clusters. Phylogenetic analysis based on 16S rRNA, atpD, glnII, gyrB, nifH and nodC gene sequences revealed distinct and novel evolutionary lineages related to the genus Rhizobium and Mesorhizobium, with some of them being very close to Mesorhizobium australicum. However, the phylogenetic analysis of glnII and nifH genes of some isolates showed incongruency.

Improving SCOBY starter using co-culture of tapai and bakery yeast

Abstract. Urbahillah A, Jayus J, Nurhayati N. 2021. Improving SCOBY starter using co-culture of tapai and bakery yeast. Biodiversitas 22: 4617-4624. Kombucha is a beverage fermented by a symbiotic bacteria and yeast known as SCOBY (Symbiotic Culture of Bacteria and Yeast). Bacteria and yeast contribute to the formation of organic acids, aroma, taste, and flavor of kombucha. The commercial yeasts used in Indonesian are baker’s yeast and tapai yeast. This study was conducted to develop SCOBYco-culture with tapai yeast and baker’s yeast and evaluate its activity. The ingredients for the kombucha were cascara, water, and sugar, which were fermented with three formula starter, i.e. original SCOBY 10% w/v (SN), co-culture SCOBY 10% w/v with 0.1% w/v of baker’s yeast (SNR), and co-culture SCOBY 10% w/v with tapai yeast 0.1% w/v (SNT). The starter activity were determined based on the OD (Optical Density) value. Yeast screening was carried out on the dominant starter population. Furthermore, morphologically yeast was identified based on colony type, color, and shape of cell. Then yeast was identified by their fermentation profile using API 20C Aux Kit. Isolate A showed white colony with convex elevation and the cell was round-shaped. Colony of isolate B and isolate C were creamy in color and oval cell shaped. The API results revealed that the first isolate was identified as Candida famata, second isolate was as Candida krusei, and the third isolate was as Candida magnoliae. Three types of fungi were found from SCOBY, namely Mucor sp., Trichoderma sp., and Fusarium sp. Mucor sp. has non-septate hyphae, and round black spores. Trichoderma sp. has septate hyphae, greenish-white spores, and the conidia have the shape of globose to ellipsoidal Fusarium sp. has a mold with septate hyphae, yellowish-white colonies, and the conidia have the shape of obovoid. Bacteria, yeast, and mold present in the medium form a powerful symbiosis for produce metabolite.