Effect of Carrier Materials, Coinoculation and Sterilization on Survival of Plant Growth Promoting Microbes

Samuel Mwafulirwa *

Ministry of Agriculture, Chitedze Agricultural Research Station Box 158 Lilongwe, Malawi.

Fortune M. Kanyada

Department of Forest, Mchinji Forest Office, C/O Nkhalango House, P.O. Box-30048 Lilongwe, Malawi.

*Author to whom correspondence should be addressed.


The study was conducted to investigate diverse carrier materials out of agricultural and environmental waste, that plays a role in maintaining the shelf life of plant growth promoting microbes (PGPM) at room temperature for locally produced inoculants in Malawi. Five different formulations divided into sterilized and unsterilized were prepared, using different carrier materials namely; rice bran plus plant extract (RBP), biochar plus plant extract (BP), Filter mud plus plant extract (FMP), rice bran, biochar and plant extracts (RBCP), filter mud, biochar and plant extracts (FMBP). Carrier materials were packed in polyethylene pack (six per each treatment), thereafter each treatment was divided into sterilized and unsterilized. Each treatment was inoculated with either single or multiple inoculants. Survival of PGPM, was based on colony forming units (CFU) on specific selective media namely: modified yeast extract mannitol, pikovskaya’s, Alexandria and basal media for nitrogen fixing microbes, phosphate, potassium and zinc solubilising media respectively. Results revealed that encapsulated formulation of based combination formulation of RBCP in both single and multiple inoculants exerted high stable numbers of PGRM along the storage compared to other formulations. The results also show that unsterilized formulations exert high numbers compared to sterilized which is as a result of hydrogen peroxide accumulation during sterilization. The study reveals that filter mud based formulations currently used in both single and multiple inoculants is not favorable for local environments because microbial numbers decrease after 20 days at room temperature. This makes filter mud formulations usage not favorable for rural smallholder farmers with no refrigeration facilities.

Keywords: Carrier materials, agricultural and environmental waste, plant growth promoting microbes, inoculants

How to Cite

Mwafulirwa, S., & Kanyada, F. M. (2023). Effect of Carrier Materials, Coinoculation and Sterilization on Survival of Plant Growth Promoting Microbes. Asian Plant Research Journal, 11(3), 22–28. https://doi.org/10.9734/aprj/2023/v11i3212


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Rao. Recent Advances in Biological Nitrogen Fixation in Agricultural Systems. 2014;(2):359-378. doi:10.16943/ptinsa/2014/v80i2/55114

Hungria M, Nogueira MA, Araujo RS. Soybean Seed Co-Inoculation with Bradyrhizobium spp . and Azospirillum brasilense : A New Biotechnological Tool to Improve Yield and Sustainability. 2015:811-817.

Souza R De, Ambrosini A, Passaglia LMP. Plant Growth-promoting Bacteria as Inoculants in Agricultural Soils. 2015; 419:401-419.

Abreu CS De, Figueiredo JEF, Oliveira CA, Santos VL, Gomes EA. Maize Endophytic Bacteria as Mineral Phosphate Solubilizers. 2016;16(1):1-13.

Carriers BI, Vanek SJ, Thies J, Wang B, Hanley K, Lehmann J. Microbial & Biochemical Technology Pore-Size and Water Activity Effects on Survival of Rhizobium tropici in. 2016;8(4):296-306. DOI:10.4172/1948-5948.1000300

S, Balume IK, et al. Shelf-life of legume inoculants in Different Carrier Materials Available in East Africa. 2015;23(4): 379-385.

Redao C. Biochar as a Potential inoculant Carrier for Plant-beneficial Bacteria; 2016.

El-fattah DAA, Eweda WE, Zayed MS, Hassanein MK. Effect of carrier materials , sterilization method, and storage temperature on survival and biological activities of Azotobacter chroococcum inoculant. Ann Agric Sci. 2013;58(2): 111-118. DOI:10.1016/j.aoas.2013.07.001

Bashan Y, de-Bashan LE, Prabhu SR, Hernandez JP. Advances in plant growth-promoting bacterial inoculant technology: Formulations and practical perspectives (1998-2013). Plant Soil. 2014;378(1-2): 1-33.


Arora NK, Tiwari S, Singh R. Plant Pathology & Microbiology Comparative Study of Different Carriers Inoculated with Nodule Forming and Free Living Plant Growth Promoting Bacteria Suitable for Sustainable Agriculture. 2014; 5:2-4. DOI:10.4172/2157-7471.1000229

Chaot W, Alexander M. Carriers for Rhizobium Inoculants. 1984;47(1):94-97.

Pindi PK. Liquid Microbial Consortium- A Potential Tool for Sustainable Soil Health. J Biofertilizers Biopestic. 2012;03(04). DOI:10.4172/2155-6202.1000124

Bashan Y. Pll S0734-9750(98)00003-2 ELSEVIER. 1998;16(4):729-770.

Gopalakrishnan S, Sathya A, Vijayabharathi R, Srinivas V. Formulations of Plant Growth- Promoting Microbes for Field. Published Online. 2016:239-251. DOI:10.1007/978-81-322-2644-4

González-andrés F. Formulation of a Highly Effective Inoculant for Common Bean Based on an Autochthonous Elite Strain of Rhizobium leguminosarum bv . Insights Into Its Agronomic Performance. 2019;10(December):1-16.


Sparrow SD, Ham GE. Survival of Rhizobium phaseoli in Six Carrier Materials ’. 1983;75:181-184.

Srinivasan R, Yandigeri MS, Kashyap S, Alagawadi AR. Effect of salt on survival and P-solubilization potential of phosphate solubilizing microorganisms from salt affected soils. Saudi J Biol Sci. 2012;19(4):427-434.


Adhya TK, Kumar N, Reddy G, Podile AR, Bee H, Samantaray B. Microbial mobilization of soil phosphorus and sustainable P management in agricultural soils. Curr Sci. 2015;108(7).

Karpagam T, Nagalakshmi PK. Original Research Article Isolation and characterization of Phosphate Solubilizing Microbes from Agricultural soil. 2014; 3(3):601-614.

Liu M, Liu X, Cheng B sen, et al. Selection and evaluation of phosphate-solubilizing bacteria from Grapevine Rhizospheres for Use as Biofertilizers. 2016;14(4).

Mathew L, Sharad V, Divya A, Rishi S, Mandhan P. Cost-effective screening and isolation of xylano-cellulolytic positive microbes from termite gut and termitarium. 3 Biotech. 2017;7(2):1-7. DOI:10.1007/s13205-017-0733-6

Ivan P, Júnior F, Rohr TG, Oliveira PJ De, Xavier GR. Polymers as carriers for rhizobial Inoculant Formulations. 2009;(1): 1184-1190.

Campbell RM, Anderson NM, Daugaard DE, Naughton HT. Financial viability of biofuel and biochar production from forest biomass in the face of market price volatility and uncertainty. Appl Energy. 2018;230(August):330-343.


Furtak K, Gałązka A. Edaphic Factors And Their Influence On The Microbiological Biodiversity Of The Soil Environment. Published Online 2019:375-384. DOI:10.21307/PM-2019.58.4.375

Ma Y. Seed coating with beneficialmicroorganisms for precision agriculture.Biotechnology Advances. 2019;37(7):107423.

Nishiyama E, Higashi K, Mori H, Suda K, Nakamura H. The Relationship Between Microbial Community Structures and Environmental Parameters Revealed by Metagenomic Analysis of Hot Spring Water in the Kirishima Area. 2018;6(December). DOI:10.3389/fbioe.2018.00202

Id RA martins, Carvalho P, Miranda D. Edible ectomycorrhizal fungi and Cistaceae . A study on compatibility and fungal ecological strategies. Published Online. 2019:1-16.

Głuszek S, Sas-paszt L, Sumorok B, Kozera R. Biochar-Rhizosphere Interactions – a Review. 2017;66(2): 151-161.

Oelbermann M. conditioned biochar on soil organic carbon in temperate soils using the Century Soil Organic Matter model Evaluation of the long ‐ term effects of pre ‐ conditioned biochar on soil organic carbon in temperate soils using the Century Soil Organic Matter model Matthew Dil and Maren Oelbermann *. Published Online; 2017.

Tronto J. Characterization of biochars from different sources and evaluation. Published online 2017:395-403.


Głodowska M, Schwinghamer T, Husk B, Smith D. Biochar Based Inoculants Improve Soybean Growth and Nodulation. Published online 2017:1048-1064. DOI:10.4236/as.2017.89076

Meiirkhanuly Z. Evaluation of biochar for mitigation of ammonia , hydrogen sulfide , odorous volatile organic compounds, and greenhouse gases emissions from swine manure. Published online 2019.

Harter J, El-hadidi M, Huson DH, Kappler A, Behrens S. Soil biochar amendment affects the diversity of nosZ transcripts : Implications for N 2 O formation. Published Online. 2017:1-14. DOI:10.1038/s41598-017-03282-y

H AR, I JC, A FD, J MB, C SK. Characterisation and evaluation of biochars for their application as soil amendment Opportunities and constraints for biochar technology in Australian agriculture : Looking Beyond Carbon Sequestration; 2010. DOI:10.1071/SR10058

Mary GS, Niveditha PSS, Mary GS. Production, characterization and evaluation of biochar from pod (Pisum sativum), leaf (Brassica oleracea) and peel (Citrus sinensis) wastes. Int J Recycl Org Waste Agric. 2016;5(1):43-53.


Physics R, Kennedy IR, Thies JE. microorganisms used as bio-fertilisers and bio-pesticides Development of high quality carrier materials for ® Eld Delivery of Key Microorganisms used as Bio-fertilisers and. 2000;(March).


Rajasekar K, Daniel T, Karmegam N. Microbial Enrichment of Vermicompost. 2012;2012. DOI:10.5402/2012/946079

Plains S, Argaw A. Response of Soybean to Inoculation with Bradyrhizobium spp . in Saline Soils of East African Journal of Sciences (2014) Response of Soybean to Inoculation with Bradyrhizobium spp . in Saline Soils of Shinille. 2015;(October).

Bala A, Karanja N, Murwira M, Lwimbi L, Abaidoo R, Giller K. Production and use of Rhizobial inoculants in Africa N2Africa Putting nitrogen fixation to work for smallholder farmers in Africa. 2011;3.

Mendes GDO, Zafra L, Vassilev B, Silva R, Ribeiro I. Biochar Enhances Aspergillus niger Rock Phosphate Solubilization by. 2014;80(10):3081-3085. DOI:10.1128/AEM.00241-14

Tittabutr P, Teamthisong K, Buranabanyat B, Teaumroong N. Gamma Irradiation and Autoclave Sterilization Peat and Compost as the Carrier for Rhizobial Inoculant Production. 2012;4(12):59-67. DOI:10.5539/jas.v4n12p59