ABSTRAKNannochloropsis sp. merupakan salah satu jenis mikroalga yang banyakmengandung nutrisi. Dengan demikian Nannochloropsis sp. sebenarnyamempunyai potensi yang besar dan menjanjikan sebagai sumber nutrisi pangandan bahan baku biomedis. Pada penelitian ini akan dilakukan teknik untukmeningkatkan produksi biomassa mikroalga Nannochloropsis sp. denganpengaturan pencahayaan yaitu mencari Iμmax,opt dari beberapa inokulum dilanjutkandengan perlakuan alterasi pencahayaan. Kultivasi Nannochloropsis sp. dilakukandalam medium walne pada temperatur 29°C, tekanan operasi 1 atm, sumberpencahayaan lampu 20W/12V/50Hz, dan konsentrasi CO2 5 %. Hasilnyamenunjukkan bahwa alterasi mampu meningkatkan kemampuan produksibiomassa sampai 1.22 kali lipat lebih tinggi dibandingkan pencahayaan padaintensitas tetap dengan jumlah inokulum yang sama serta masa kultivasi yanglebih singkat (204 jam) dan energi untuk produksi biomassa (Ex) yang lebihefisien (793,75 kJ/g). Selain itu, pada perlakuan alterasi juga didapatkan nilai ratarataqco2 lebih besar 1.08 kali lipat (37,69 g/gsel.jam), nilai CTR (Carbon TransferRate) lebih besar 2.03 kali lipat (25,55 g/L.jam) dan konsentrasi [HCO3-] lebihbesar 1.11 kali lipat (0.0245 M) dibanding pencahayaan pada intensitas tetap.Mikroalga yang dikultivasi pada alterasi pencahayaan juga memiliki kadar lipidlebih tinggi yaitu (39.6%). Pencahayaan yang kuat secara tidak langsung memangdapat mempengaruhi akumulasi lemak jika dikombinasikan dengan tekanan lainatau keberadaan CO2 berlebih.

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ABSTRACTNannochloropsis sp. has a great potential and promising as a nutritional source of

food and biomedical materials in consideration of it contain many nutrients. On

the other hand, environmental factors affecting growth rates and gains in the

cultivation of cells also have an impact on levels of lipids and oils and its

composition in Nannochloropsis sp. One of the influential factors is lighting.

Based on these facts, then on this study will be conducted a techniques to increase

biomass production of microalgae Nannochloropsis sp. by the lighting setting that

are tailored to the growth. Lighting arrangement is done by finding Iμmax,opt from

several inoculum followed by the alteration lighting treatment which is expected

could reduce the self-shading effect that occurs in cultured microalgae in a

photobioreactor, in order to obtain optimal growth rate and increased the biomass

production of Nannochloropsis sp. Alteration of lighting treatment on the

cultivation of Nannochloropsis sp. in the walne medium on 29 °C temperature

operating conditions, operating pressure of 1 atm, lighting sources

20W/12V/50Hz, and 5% CO2 concentration was successful in increasing biomass

production capability up to 1:22-fold higher than in continuous illumination with

the same amount of inoculum and a shorter cultivation period (204 hours) and for

the production of biomass energy (Ex) is more efficient (793748.66 J/g). In

addition, the alteration treatment is also found CO2 fixation and cell activity fold

higher compared with continuous illumination at Iμmax,opt it with the same amount

of inoculum. As shown by the average value of alterations qco2 and CTR on each

lightingfold larger 1:08 and 2:03 times as well as the concentration of [HCO3-]

1:11-fold higher (0.0245 M). Microalgae are cultivated on the alteration of

lighting also has a higher lipid content (39.6%) compared lipid levels in

continuous light. Strong lighting is able to indirectly affect the accumulation of fat

when combined with other pressures, or the presence of excess CO2.