Polyhydroxybutyrate (PHB) are biodegradable materials, which are accumulated to store carbon and energy in various microorganisms.                                   

Soil samples used for the study were collected from groundnut farm garden. The isolates were screened for PHB production using sudan III stain as well as submerged fermentation. Four (4) of the best PHB producing bacteria were selected for further study. A total of twenty one (21) bacteria were isolated form the soil sample in which Bacillus sp had the highest percentage frequency of occurrence (54.5%). Follow in order by Enterococcus sp  (13.63%), Veillonella sp  (9.1%),  Micrococcus sp. (4.5 %), Corynebacterium sp.(4.5%) Yersinia Pestis (4.5%), Lactobacillus fermenti (4.5%) and Citrobacter sp. (4.5%).

The fermentation pattern of PHB production was studied using Nitrogen source. NH4Cl was found to be the best nitrogen source (1.560a) for growth of PHB producing bacteria  (Citrobacter sp) while maximum PHB production  (1.899a) was observed in Citrobacter sp when KNO3 was used as nitrogen source.

The study carried out shown that nitrogen sources significantly influence the production of PHB .


Title page





Table of content


1.0 Introduction

1.1 Aims and objectives

1.2 Statement of problem

1.3 Justification


2.0 Literature review


3.0 Materials and method

3.1 Preparation of media

3.2 Isolation of bacterial from soil samples

3.3 Maintenance of culture

3.4 Identification of bacterial isolates

3.4.1 Morphological characterization

3.4.2 Biochemical characterization

3.5 Screening o isolate for PHB production using staining techniques.

3.6 PHB production

3.7 PHB extraction


4.0 Result and discussion


Conclusion and appendix



Polyhydroxybutyrate (PHB) is one of the polyhydroxyalkanoates (PHAs) which has biodegradable and biocompatible properties. They are adopted in the biomedical field, in for example, medical implants and drug delivery carriers (Keshavarz and Roy, 2010).

Polyhydroxybutyrate was discovered and identified as a granular component in bacterial cells. PHB can grow in a wide variety of natural environment and is the reserve polymer (intracellular granules) found in many types of bacteria in nature e.g. in soil, sea water, sewage sludge or compost.

Polyhydroxyalkanoates (PHAs) can be classified into two groups depending on the number of carbon atoms in the monomer unit: short-chain-length. (SCL-PHA) 3-5 carbon atom containing monomer and medium chain-length (MCL-PHAs), 6-14 carbon atom containing monomers (Steinbuchel and Valentin, 1995).

The discovery of a polyester by Smet et al. (1983) was the first report of accumulation of medium-chain-length (MCl-PHAs), having constituents of 6-14 carbon atoms in axenic culture (Smet et al., 1983).

Currently, more than 140 hydroxyalkanoic acid have been identified as constituent of polyhydroxyalkanoates (PHAs) representing a versatile class of microbial polymer (Steinbuchel and Valentin, 1995). Besides linear and branched 3-4-,5- and 6-hydroxyalkanoates, various functionalized PHAs constituents such as polyhydroxyalkanoates (PHAs) containing halogenated or aromatic side chains have been described (Abe et al., 1990).

The physical properties of the homopolymer of hydroxybutyrate (PHB) are similar to those of poly propylene, for example regarding melting point, crystallinity, glass transition temperatures etc, and represent a stiff and brittle material (Hocking and Marchessault, 1994). The properties are improved in copolymers containing up to 25 mol% 3-hydroxyvalerate (3HV), where toughness and flexibility are increased and the decrease in crystallinity and melting point advance the melt-processing of the polymer without being degraded(Marchessault and Yu, 2002).

Therefore, the poly (3HB-CO-3HV) copolymer gained industrial interest and in the late 1980s, commercialization under the trade name Biopol was initiated (Holmer et al., 1984). Biopol can be processed to useful materials by various processes such, as extrusion, injection molding, fiber spinning, coating or foaming. Because of the versatile applications as thermoplastic biopolymers, polyhydroxyalkanoates (PHAs) can also be used for natural fiber composites or as binder in paints and for various application in medicine and pharmacy such as tissue engineering (Kessler et al., 1999)

Polyhydroxylbutyrate(PHB) is a commonly found substance and readily biodegradable are aerobically and anaerobically. Microbes can use polyhydroxylbutyrate (PHB) exists in the cytoplasmic fluid in the form of crystalline granule about 0.5μm in diameter. Beta-hydroxybutyrate is connected by ester linkage and from polyhydroxybutyrate (Andreson and Dawes, 1990). This can be extracted from the cells as native granule or by solvent extraction (Doi and lee, 1990) and processed in the way as polypropylene. 

These biopolymers were also found to increase the resistance of bacteria (Tombolini and Nuti, 1989). Lemoigne, Grelet and Croson (1950) draw attention to the different amount of poly-beta – hydroxybutyrate obtained by Bacterim megaterium on different media and Maraca and Wilkinson (1958) showed that more of the substance was formed as the glucose concentration of the growth medium was increased; the subsequent depletion of the product during the later stage of growth suggested a storage function. They also showed that organism rich in poly-beta-hydroxybutyrate had a slower rate of autolysis than organisms poor in poly-beta-hydroxybutyrate. It is probable; therefore, that poly-beta-hydroxybutyrate act as a reserve carbon and energy source. Tinelli (1955) found that the major part of the material was metabolized at sporulation and deduced that the two processes were intimately connected (Kato et al., 1992) 

The bacterium capable of producing polyhydroxybutyrate has been identified in more than twenty (20) bacterial genera, including Azotobacter, Bacillus, Beijernickia, Pseudomonas. Alcaligenes, Rhizobium and Rhodospirillum (Sudesh et al., 2000). Many researchers have explained that soil bacteria generally produce polyhydroxybutyrate. Polyhydroxybutyrate PHB) production increases if ambient conditions (PH, temperature, nutrients) are made available (Hanzlikova et al., 1985).

Polyhydroxyalkanoate is one such biodegradable microbial polymer which is accumulated in bacteria as intracellular storage granules in the presence of excess carbon sources and limited nitrogen source (Anderson and Dawes, 1990). 

The polymer is known to occur as intracellular granules in several genera of micro-organisms. The granules are synthesized by prokaryotes using fatty  acids, sugars and other carbon sources (Atkins and kennedy, 1985). Polyhydroxybutyrate is insoluble in water, resistant to ultraviolet radiation and is impermeable to oxygen and is very much suitable for use as food packaging material. This polymer is readily degraded in the soil and sewage and can be processed using the extrusion technology that is currently used in making polyethylene or polypropylene films (Byrom, 1987). The polyhydroxyalkanoate content and its composition are influenced mainly by the strain of the micro-organisms (Halami, 2008). To achieve a cost effective polyhydroxyalkanoate production, the availability of an efficient bacterial strain is a prerequisite and is a focus of interest for many investigation (Green span et al., 1985).

The polyhydroxybutyrate production using inexpensive carbon sources in the form of starch by the indigenous strain can be advantageous as the complex starch substrates can be used directly without involvement of any hydrolysis step (Hahn et al., 1995).

Polyhydroxybutyrate (PHB) is used in food packaging, plastic films, surgical sutures (Stitching of the edges of a wound or incision), controlled drug deliver e.t.c (kim et al., 1994). This bioplastic has many applications in bone plates, nails, screws and in the treatment of osteomyclitis (Hanzlikova et al., 1985).


1. Isolation and biochemical identification of       polyhydroxybutyrate (PHB) producing bacteria from soil.   

2. Screening of polyhydroxybutyrate (PHB) producing bacteria isolated from soil. 

3. Polyhydrobutyrate (PHB) Production.        

4. Determination of effect of different nitrogen sources on growth and polyhydroxybutyrate (PHB) production, 


The accumulation of these non-degradable plastic in the environment is a menacing (threating) draw back increasing day by day. Oil based polymers take many years to degrade which poses an environment problem in some areas, and causes deleterious effects to wild life. To overcome this, production of environmental friendly plastic have been discovered. 


The continuous exhaustion of fossil fuels led to the research for the production of bio-degradable plastic from renewable sources the production of biodegradable polymers from renewable resources is the need of the hour, in the face of these ecological facts.



RESEARCHWAP.COM is an online repository for free project topics and research materials, articles and custom writing of research works. We’re an online resource centre that provides a vast database for students to access numerous research project topics and materials. guides and assist Postgraduate, Undergraduate and Final Year Students with well researched and quality project topics, topic ideas, research guides and project materials. We’re reliable and trustworthy, and we really understand what is called “time factor”, that is why we’ve simplified the process so that students can get their research projects ready on time. Our platform provides more educational services, such as hiring a writer, research analysis, and software for computer science research and we also seriously adhere to a timely delivery.


Please feel free to carefully review some written and captured responses from our satisfied clients.

  • "Exceptionally outstanding. Highly recommend for all who wish to have effective and excellent project defence. Easily Accessable, Affordable, Effective and effective."

    Debby Henry George, Massachusetts Institute of Technology (MIT), Cambridge, USA.
  • "I saw this website on facebook page and I did not even bother since I was in a hurry to complete my project. But I am totally amazed that when I visited the website and saw the topic I was looking for and I decided to give a try and now I have received it within an hour after ordering the material. Am grateful guys!"

    Hilary Yusuf, United States International University Africa, Nairobi, Kenya.
  • " is a website I recommend to all student and researchers within and outside the country. The web owners are doing great job and I appreciate them for that. Once again, thank you very much "" and God bless you and your business! ."

    Debby Henry George, Massachusetts Institute of Technology (MIT), Cambridge, USA.
  • "I love what you guys are doing, your material guided me well through my research. Thank you for helping me achieve academic success."

    Sampson, University of Nigeria, Nsukka.
  • " is God-sent! I got good grades in my seminar and project with the help of your service, thank you soooooo much."

    Cynthia, Akwa Ibom State University .
  • "Great User Experience, Nice flows and Superb functionalities.The app is indeed a great tech innovation for greasing the wheels of final year, research and other pedagogical related project works. A trial would definitely convince you."

    Lamilare Valentine, Kwame Nkrumah University, Kumasi, Ghana.
  • "Sorry, it was in my spam folder all along, I should have looked it up properly first. Please keep up the good work, your team is quite commited. Am grateful...I will certainly refer my friends too."

    Elizabeth, Obafemi Awolowo University
  • "Am happy the defense went well, thanks to your articles. I may not be able to express how grateful I am for all your assistance, but on my honour, I owe you guys a good number of referrals. Thank you once again."

    Ali Olanrewaju, Lagos State University.
  • "My Dear Researchwap, initially I never believed one can actually do honest business transactions with Nigerians online until i stumbled into your website. You have broken a new legacy of record as far as am concerned. Keep up the good work!"

    Willie Ekereobong, University of Port Harcourt.
  • "WOW, SO IT'S TRUE??!! I can't believe I got this quality work for just 3k...I thought it was scam ooo. I wouldn't mind if it goes for over 5k, its worth it. Thank you!"

    Theressa, Igbinedion University.
  • "I did not see my project topic on your website so I decided to call your customer care number, the attention I got was epic! I got help from the beginning to the end of my project in just 3 days, they even taught me how to defend my project and I got a 'B' at the end. Thank you so much, infact, I owe my graduating well today to you guys...."

    Joseph, Abia state Polytechnic.
  • "My friend told me about ResearchWap website, I doubted her until I saw her receive her full project in less than 15 miniutes, I tried mine too and got it same, right now, am telling everyone in my school about, no one has to suffer any more writing their project. Thank you for making life easy for me and my fellow students... Keep up the good work"

    Christiana, Landmark University .
  • "I wish I knew you guys when I wrote my first degree project, it took so much time and effort then. Now, with just a click of a button, I got my complete project in less than 15 minutes. You guys are too amazing!."

    Musa, Federal University of Technology Minna
  • "I was scared at first when I saw your website but I decided to risk my last 3k and surprisingly I got my complete project in my email box instantly. This is so nice!!!."

    Ali Obafemi, Ibrahim Badamasi Babangida University, Niger State.
  • To contribute to our success story, send us a feedback or please kindly call 2348037664978.
    Then your comment and contact will be published here also with your consent.

    Thank you for choosing